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33 .Dd Jan 05, 2019
34 .Dt ZFS 8 SMM
35 .Os Linux
36 .Sh NAME
37 .Nm zfs
38 .Nd configures ZFS file systems
39 .Sh SYNOPSIS
40 .Nm
41 .Fl ?V
42 .Nm
43 .Cm create
44 .Op Fl p
45 .Oo Fl o Ar property Ns = Ns Ar value Oc Ns ...
46 .Ar filesystem
47 .Nm
48 .Cm create
49 .Op Fl ps
50 .Op Fl b Ar blocksize
51 .Oo Fl o Ar property Ns = Ns Ar value Oc Ns ...
52 .Fl V Ar size Ar volume
53 .Nm
54 .Cm destroy
55 .Op Fl Rfnprv
56 .Ar filesystem Ns | Ns Ar volume
57 .Nm
58 .Cm destroy
59 .Op Fl Rdnprv
60 .Ar filesystem Ns | Ns Ar volume Ns @ Ns Ar snap Ns
61 .Oo % Ns Ar snap Ns Oo , Ns Ar snap Ns Oo % Ns Ar snap Oc Oc Oc Ns ...
62 .Nm
63 .Cm destroy
64 .Ar filesystem Ns | Ns Ar volume Ns # Ns Ar bookmark
65 .Nm
66 .Cm snapshot
67 .Op Fl r
68 .Oo Fl o Ar property Ns = Ns Ar value Oc Ns ...
69 .Ar filesystem Ns @ Ns Ar snapname Ns | Ns Ar volume Ns @ Ns Ar snapname Ns ...
70 .Nm
71 .Cm rollback
72 .Op Fl Rfr
73 .Ar snapshot
74 .Nm
75 .Cm clone
76 .Op Fl p
77 .Oo Fl o Ar property Ns = Ns Ar value Oc Ns ...
78 .Ar snapshot Ar filesystem Ns | Ns Ar volume
79 .Nm
80 .Cm promote
81 .Ar clone-filesystem
82 .Nm
83 .Cm rename
84 .Op Fl f
85 .Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot
86 .Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot
87 .Nm
88 .Cm rename
89 .Op Fl fp
90 .Ar filesystem Ns | Ns Ar volume
91 .Ar filesystem Ns | Ns Ar volume
92 .Nm
93 .Cm rename
94 .Fl r
95 .Ar snapshot Ar snapshot
96 .Nm
97 .Cm list
98 .Op Fl r Ns | Ns Fl d Ar depth
99 .Op Fl Hp
100 .Oo Fl o Ar property Ns Oo , Ns Ar property Oc Ns ... Oc
101 .Oo Fl s Ar property Oc Ns ...
102 .Oo Fl S Ar property Oc Ns ...
103 .Oo Fl t Ar type Ns Oo , Ns Ar type Oc Ns ... Oc
104 .Oo Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot Oc Ns ...
105 .Nm
106 .Cm set
107 .Ar property Ns = Ns Ar value Oo Ar property Ns = Ns Ar value Oc Ns ...
108 .Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot Ns ...
109 .Nm
110 .Cm get
111 .Op Fl r Ns | Ns Fl d Ar depth
112 .Op Fl Hp
113 .Oo Fl o Ar field Ns Oo , Ns Ar field Oc Ns ... Oc
114 .Oo Fl s Ar source Ns Oo , Ns Ar source Oc Ns ... Oc
115 .Oo Fl t Ar type Ns Oo , Ns Ar type Oc Ns ... Oc
116 .Cm all | Ar property Ns Oo , Ns Ar property Oc Ns ...
117 .Oo Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot Ns | Ns Ar bookmark Oc Ns ...
118 .Nm
119 .Cm inherit
120 .Op Fl rS
121 .Ar property Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot Ns ...
122 .Nm
123 .Cm upgrade
124 .Nm
125 .Cm upgrade
126 .Fl v
127 .Nm
128 .Cm upgrade
129 .Op Fl r
130 .Op Fl V Ar version
131 .Fl a | Ar filesystem
132 .Nm
133 .Cm userspace
134 .Op Fl Hinp
135 .Oo Fl o Ar field Ns Oo , Ns Ar field Oc Ns ... Oc
136 .Oo Fl s Ar field Oc Ns ...
137 .Oo Fl S Ar field Oc Ns ...
138 .Oo Fl t Ar type Ns Oo , Ns Ar type Oc Ns ... Oc
139 .Ar filesystem Ns | Ns Ar snapshot
140 .Nm
141 .Cm groupspace
142 .Op Fl Hinp
143 .Oo Fl o Ar field Ns Oo , Ns Ar field Oc Ns ... Oc
144 .Oo Fl s Ar field Oc Ns ...
145 .Oo Fl S Ar field Oc Ns ...
146 .Oo Fl t Ar type Ns Oo , Ns Ar type Oc Ns ... Oc
147 .Ar filesystem Ns | Ns Ar snapshot
148 .Nm
149 .Cm projectspace
150 .Op Fl Hp
151 .Oo Fl o Ar field Ns Oo , Ns Ar field Oc Ns ... Oc
152 .Oo Fl s Ar field Oc Ns ...
153 .Oo Fl S Ar field Oc Ns ...
154 .Ar filesystem Ns | Ns Ar snapshot
155 .Nm
156 .Cm project
157 .Oo Fl d Ns | Ns Fl r Ns Oc
158 .Ar file Ns | Ns Ar directory Ns ...
159 .Nm
160 .Cm project
161 .Fl C
162 .Oo Fl kr Ns Oc
163 .Ar file Ns | Ns Ar directory Ns ...
164 .Nm
165 .Cm project
166 .Fl c
167 .Oo Fl 0 Ns Oc
168 .Oo Fl d Ns | Ns Fl r Ns Oc
169 .Op Fl p Ar id
170 .Ar file Ns | Ns Ar directory Ns ...
171 .Nm
172 .Cm project
173 .Op Fl p Ar id
174 .Oo Fl rs Ns Oc
175 .Ar file Ns | Ns Ar directory Ns ...
176 .Nm
177 .Cm mount
178 .Nm
179 .Cm mount
180 .Op Fl Olv
181 .Op Fl o Ar options
182 .Fl a | Ar filesystem
183 .Nm
184 .Cm unmount
185 .Op Fl f
186 .Fl a | Ar filesystem Ns | Ns Ar mountpoint
187 .Nm
188 .Cm share
189 .Fl a | Ar filesystem
190 .Nm
191 .Cm unshare
192 .Fl a | Ar filesystem Ns | Ns Ar mountpoint
193 .Nm
194 .Cm bookmark
195 .Ar snapshot bookmark
196 .Nm
197 .Cm send
198 .Op Fl DLPRbcehnpvw
199 .Op Oo Fl I Ns | Ns Fl i Oc Ar snapshot
200 .Ar snapshot
201 .Nm
202 .Cm send
203 .Op Fl LPcenvw
204 .Op Fl i Ar snapshot Ns | Ns Ar bookmark
205 .Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot
206 .Nm
207 .Cm send
208 .Op Fl Penv
209 .Fl t Ar receive_resume_token
210 .Nm
211 .Cm receive
212 .Op Fl Fhnsuv
213 .Op Fl o Sy origin Ns = Ns Ar snapshot
214 .Op Fl o Ar property Ns = Ns Ar value
215 .Op Fl x Ar property
216 .Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot
217 .Nm
218 .Cm receive
219 .Op Fl Fhnsuv
220 .Op Fl d Ns | Ns Fl e
221 .Op Fl o Sy origin Ns = Ns Ar snapshot
222 .Op Fl o Ar property Ns = Ns Ar value
223 .Op Fl x Ar property
224 .Ar filesystem
225 .Nm
226 .Cm receive
227 .Fl A
228 .Ar filesystem Ns | Ns Ar volume
229 .Nm
230 .Cm allow
231 .Ar filesystem Ns | Ns Ar volume
232 .Nm
233 .Cm allow
234 .Op Fl dglu
235 .Ar user Ns | Ns Ar group Ns Oo , Ns Ar user Ns | Ns Ar group Oc Ns ...
236 .Ar perm Ns | Ns @ Ns Ar setname Ns Oo , Ns Ar perm Ns | Ns @ Ns
237 .Ar setname Oc Ns ...
238 .Ar filesystem Ns | Ns Ar volume
239 .Nm
240 .Cm allow
241 .Op Fl dl
242 .Fl e Ns | Ns Sy everyone
243 .Ar perm Ns | Ns @ Ns Ar setname Ns Oo , Ns Ar perm Ns | Ns @ Ns
244 .Ar setname Oc Ns ...
245 .Ar filesystem Ns | Ns Ar volume
246 .Nm
247 .Cm allow
248 .Fl c
249 .Ar perm Ns | Ns @ Ns Ar setname Ns Oo , Ns Ar perm Ns | Ns @ Ns
250 .Ar setname Oc Ns ...
251 .Ar filesystem Ns | Ns Ar volume
252 .Nm
253 .Cm allow
254 .Fl s No @ Ns Ar setname
255 .Ar perm Ns | Ns @ Ns Ar setname Ns Oo , Ns Ar perm Ns | Ns @ Ns
256 .Ar setname Oc Ns ...
257 .Ar filesystem Ns | Ns Ar volume
258 .Nm
259 .Cm unallow
260 .Op Fl dglru
261 .Ar user Ns | Ns Ar group Ns Oo , Ns Ar user Ns | Ns Ar group Oc Ns ...
262 .Oo Ar perm Ns | Ns @ Ns Ar setname Ns Oo , Ns Ar perm Ns | Ns @ Ns
263 .Ar setname Oc Ns ... Oc
264 .Ar filesystem Ns | Ns Ar volume
265 .Nm
266 .Cm unallow
267 .Op Fl dlr
268 .Fl e Ns | Ns Sy everyone
269 .Oo Ar perm Ns | Ns @ Ns Ar setname Ns Oo , Ns Ar perm Ns | Ns @ Ns
270 .Ar setname Oc Ns ... Oc
271 .Ar filesystem Ns | Ns Ar volume
272 .Nm
273 .Cm unallow
274 .Op Fl r
275 .Fl c
276 .Oo Ar perm Ns | Ns @ Ns Ar setname Ns Oo , Ns Ar perm Ns | Ns @ Ns
277 .Ar setname Oc Ns ... Oc
278 .Ar filesystem Ns | Ns Ar volume
279 .Nm
280 .Cm unallow
281 .Op Fl r
282 .Fl s @ Ns Ar setname
283 .Oo Ar perm Ns | Ns @ Ns Ar setname Ns Oo , Ns Ar perm Ns | Ns @ Ns
284 .Ar setname Oc Ns ... Oc
285 .Ar filesystem Ns | Ns Ar volume
286 .Nm
287 .Cm hold
288 .Op Fl r
289 .Ar tag Ar snapshot Ns ...
290 .Nm
291 .Cm holds
292 .Op Fl rH
293 .Ar snapshot Ns ...
294 .Nm
295 .Cm release
296 .Op Fl r
297 .Ar tag Ar snapshot Ns ...
298 .Nm
299 .Cm diff
300 .Op Fl FHt
301 .Ar snapshot Ar snapshot Ns | Ns Ar filesystem
302 .Nm
303 .Cm program
304 .Op Fl jn
305 .Op Fl t Ar instruction-limit
306 .Op Fl m Ar memory-limit
307 .Ar pool script
308 .Op Ar arg1 No ...
309 .Nm
310 .Cm load-key
311 .Op Fl nr
312 .Op Fl L Ar keylocation
313 .Fl a | Ar filesystem
314 .Nm
315 .Cm unload-key
316 .Op Fl r
317 .Fl a | Ar filesystem
318 .Nm
319 .Cm change-key
320 .Op Fl l
321 .Op Fl o Ar keylocation Ns = Ns Ar value
322 .Op Fl o Ar keyformat Ns = Ns Ar value
323 .Op Fl o Ar pbkdf2iters Ns = Ns Ar value
324 .Ar filesystem
325 .Nm
326 .Cm change-key
327 .Fl i
328 .Op Fl l
329 .Ar filesystem
330 .Nm
331 .Cm version
332 .Sh DESCRIPTION
333 The
334 .Nm
335 command configures ZFS datasets within a ZFS storage pool, as described in
336 .Xr zpool 8 .
337 A dataset is identified by a unique path within the ZFS namespace.
338 For example:
339 .Bd -literal
340 pool/{filesystem,volume,snapshot}
341 .Ed
342 .Pp
343 where the maximum length of a dataset name is
344 .Dv MAXNAMELEN
345 .Pq 256 bytes
346 and the maximum amount of nesting allowed in a path is 50 levels deep.
347 .Pp
348 A dataset can be one of the following:
349 .Bl -tag -width "file system"
350 .It Sy file system
351 A ZFS dataset of type
352 .Sy filesystem
353 can be mounted within the standard system namespace and behaves like other file
354 systems.
355 While ZFS file systems are designed to be POSIX compliant, known issues exist
356 that prevent compliance in some cases.
357 Applications that depend on standards conformance might fail due to non-standard
358 behavior when checking file system free space.
359 .It Sy volume
360 A logical volume exported as a raw or block device.
361 This type of dataset should only be used when a block device is required.
362 File systems are typically used in most environments.
363 .It Sy snapshot
364 A read-only version of a file system or volume at a given point in time.
365 It is specified as
366 .Ar filesystem Ns @ Ns Ar name
367 or
368 .Ar volume Ns @ Ns Ar name .
369 .It Sy bookmark
370 Much like a
371 .Sy snapshot ,
372 but without the hold on on-disk data. It can be used as the source of a send
373 (but not for a receive). It is specified as
374 .Ar filesystem Ns # Ns Ar name
375 or
376 .Ar volume Ns # Ns Ar name .
377 .El
378 .Ss ZFS File System Hierarchy
379 A ZFS storage pool is a logical collection of devices that provide space for
380 datasets.
381 A storage pool is also the root of the ZFS file system hierarchy.
382 .Pp
383 The root of the pool can be accessed as a file system, such as mounting and
384 unmounting, taking snapshots, and setting properties.
385 The physical storage characteristics, however, are managed by the
386 .Xr zpool 8
387 command.
388 .Pp
389 See
390 .Xr zpool 8
391 for more information on creating and administering pools.
392 .Ss Snapshots
393 A snapshot is a read-only copy of a file system or volume.
394 Snapshots can be created extremely quickly, and initially consume no additional
395 space within the pool.
396 As data within the active dataset changes, the snapshot consumes more data than
397 would otherwise be shared with the active dataset.
398 .Pp
399 Snapshots can have arbitrary names.
400 Snapshots of volumes can be cloned or rolled back, visibility is determined
401 by the
402 .Sy snapdev
403 property of the parent volume.
404 .Pp
405 File system snapshots can be accessed under the
406 .Pa .zfs/snapshot
407 directory in the root of the file system.
408 Snapshots are automatically mounted on demand and may be unmounted at regular
409 intervals.
410 The visibility of the
411 .Pa .zfs
412 directory can be controlled by the
413 .Sy snapdir
414 property.
415 .Ss Bookmarks
416 A bookmark is like a snapshot, a read-only copy of a file system or volume.
417 Bookmarks can be created extremely quickly, compared to snapshots, and they
418 consume no additional space within the pool. Bookmarks can also have arbitrary
419 names, much like snapshots.
420 .Pp
421 Unlike snapshots, bookmarks can not be accessed through the filesystem in any
422 way. From a storage standpoint a bookmark just provides a way to reference
423 when a snapshot was created as a distinct object. Bookmarks are initially
424 tied to a snapshot, not the filesystem or volume, and they will survive if the
425 snapshot itself is destroyed. Since they are very light weight there's little
426 incentive to destroy them.
427 .Ss Clones
428 A clone is a writable volume or file system whose initial contents are the same
429 as another dataset.
430 As with snapshots, creating a clone is nearly instantaneous, and initially
431 consumes no additional space.
432 .Pp
433 Clones can only be created from a snapshot.
434 When a snapshot is cloned, it creates an implicit dependency between the parent
435 and child.
436 Even though the clone is created somewhere else in the dataset hierarchy, the
437 original snapshot cannot be destroyed as long as a clone exists.
438 The
439 .Sy origin
440 property exposes this dependency, and the
441 .Cm destroy
442 command lists any such dependencies, if they exist.
443 .Pp
444 The clone parent-child dependency relationship can be reversed by using the
445 .Cm promote
446 subcommand.
447 This causes the
448 .Qq origin
449 file system to become a clone of the specified file system, which makes it
450 possible to destroy the file system that the clone was created from.
451 .Ss "Mount Points"
452 Creating a ZFS file system is a simple operation, so the number of file systems
453 per system is likely to be numerous.
454 To cope with this, ZFS automatically manages mounting and unmounting file
455 systems without the need to edit the
456 .Pa /etc/fstab
457 file.
458 All automatically managed file systems are mounted by ZFS at boot time.
459 .Pp
460 By default, file systems are mounted under
461 .Pa /path ,
462 where
463 .Ar path
464 is the name of the file system in the ZFS namespace.
465 Directories are created and destroyed as needed.
466 .Pp
467 A file system can also have a mount point set in the
468 .Sy mountpoint
469 property.
470 This directory is created as needed, and ZFS automatically mounts the file
471 system when the
472 .Nm zfs Cm mount Fl a
473 command is invoked
474 .Po without editing
475 .Pa /etc/fstab
476 .Pc .
477 The
478 .Sy mountpoint
479 property can be inherited, so if
480 .Em pool/home
481 has a mount point of
482 .Pa /export/stuff ,
483 then
484 .Em pool/home/user
485 automatically inherits a mount point of
486 .Pa /export/stuff/user .
487 .Pp
488 A file system
489 .Sy mountpoint
490 property of
491 .Sy none
492 prevents the file system from being mounted.
493 .Pp
494 If needed, ZFS file systems can also be managed with traditional tools
495 .Po
496 .Nm mount ,
497 .Nm umount ,
498 .Pa /etc/fstab
499 .Pc .
500 If a file system's mount point is set to
501 .Sy legacy ,
502 ZFS makes no attempt to manage the file system, and the administrator is
503 responsible for mounting and unmounting the file system. Because pools must
504 be imported before a legacy mount can succeed, administrators should ensure
505 that legacy mounts are only attempted after the zpool import process
506 finishes at boot time. For example, on machines using systemd, the mount
507 option
508 .Pp
509 .Nm x-systemd.requires=zfs-import.target
510 .Pp
511 will ensure that the zfs-import completes before systemd attempts mounting
512 the filesystem. See systemd.mount(5) for details.
513 .Ss Deduplication
514 Deduplication is the process for removing redundant data at the block level,
515 reducing the total amount of data stored. If a file system has the
516 .Sy dedup
517 property enabled, duplicate data blocks are removed synchronously. The result
518 is that only unique data is stored and common components are shared among files.
519 .Pp
520 Deduplicating data is a very resource-intensive operation. It is generally
521 recommended that you have at least 1.25 GiB of RAM per 1 TiB of storage when
522 you enable deduplication. Calculating the exact requirement depends heavily
523 on the type of data stored in the pool.
524 .Pp
525 Enabling deduplication on an improperly-designed system can result in
526 performance issues (slow IO and administrative operations). It can potentially
527 lead to problems importing a pool due to memory exhaustion. Deduplication
528 can consume significant processing power (CPU) and memory as well as generate
529 additional disk IO.
530 .Pp
531 Before creating a pool with deduplication enabled, ensure that you have planned
532 your hardware requirements appropriately and implemented appropriate recovery
533 practices, such as regular backups. As an alternative to deduplication
534 consider using
535 .Sy compression=on ,
536 as a less resource-intensive alternative.
537 .Ss Native Properties
538 Properties are divided into two types, native properties and user-defined
539 .Po or
540 .Qq user
541 .Pc
542 properties.
543 Native properties either export internal statistics or control ZFS behavior.
544 In addition, native properties are either editable or read-only.
545 User properties have no effect on ZFS behavior, but you can use them to annotate
546 datasets in a way that is meaningful in your environment.
547 For more information about user properties, see the
548 .Sx User Properties
549 section, below.
550 .Pp
551 Every dataset has a set of properties that export statistics about the dataset
552 as well as control various behaviors.
553 Properties are inherited from the parent unless overridden by the child.
554 Some properties apply only to certain types of datasets
555 .Pq file systems, volumes, or snapshots .
556 .Pp
557 The values of numeric properties can be specified using human-readable suffixes
558 .Po for example,
559 .Sy k ,
560 .Sy KB ,
561 .Sy M ,
562 .Sy Gb ,
563 and so forth, up to
564 .Sy Z
565 for zettabyte
566 .Pc .
567 The following are all valid
568 .Pq and equal
569 specifications:
570 .Li 1536M, 1.5g, 1.50GB .
571 .Pp
572 The values of non-numeric properties are case sensitive and must be lowercase,
573 except for
574 .Sy mountpoint ,
575 .Sy sharenfs ,
576 and
577 .Sy sharesmb .
578 .Pp
579 The following native properties consist of read-only statistics about the
580 dataset.
581 These properties can be neither set, nor inherited.
582 Native properties apply to all dataset types unless otherwise noted.
583 .Bl -tag -width "usedbyrefreservation"
584 .It Sy available
585 The amount of space available to the dataset and all its children, assuming that
586 there is no other activity in the pool.
587 Because space is shared within a pool, availability can be limited by any number
588 of factors, including physical pool size, quotas, reservations, or other
589 datasets within the pool.
590 .Pp
591 This property can also be referred to by its shortened column name,
592 .Sy avail .
593 .It Sy compressratio
594 For non-snapshots, the compression ratio achieved for the
595 .Sy used
596 space of this dataset, expressed as a multiplier.
597 The
598 .Sy used
599 property includes descendant datasets, and, for clones, does not include the
600 space shared with the origin snapshot.
601 For snapshots, the
602 .Sy compressratio
603 is the same as the
604 .Sy refcompressratio
605 property.
606 Compression can be turned on by running:
607 .Nm zfs Cm set Sy compression Ns = Ns Sy on Ar dataset .
608 The default value is
609 .Sy off .
610 .It Sy createtxg
611 The transaction group (txg) in which the dataset was created. Bookmarks have
612 the same
613 .Sy createtxg
614 as the snapshot they are initially tied to. This property is suitable for
615 ordering a list of snapshots, e.g. for incremental send and receive.
616 .It Sy creation
617 The time this dataset was created.
618 .It Sy clones
619 For snapshots, this property is a comma-separated list of filesystems or volumes
620 which are clones of this snapshot.
621 The clones'
622 .Sy origin
623 property is this snapshot.
624 If the
625 .Sy clones
626 property is not empty, then this snapshot can not be destroyed
627 .Po even with the
628 .Fl r
629 or
630 .Fl f
631 options
632 .Pc .
633 The roles of origin and clone can be swapped by promoting the clone with the
634 .Nm zfs Cm promote
635 command.
636 .It Sy defer_destroy
637 This property is
638 .Sy on
639 if the snapshot has been marked for deferred destroy by using the
640 .Nm zfs Cm destroy Fl d
641 command.
642 Otherwise, the property is
643 .Sy off .
644 .It Sy encryptionroot
645 For encrypted datasets, indicates where the dataset is currently inheriting its
646 encryption key from. Loading or unloading a key for the
647 .Sy encryptionroot
648 will implicitly load / unload the key for any inheriting datasets (see
649 .Nm zfs Cm load-key
650 and
651 .Nm zfs Cm unload-key
652 for details).
653 Clones will always share an
654 encryption key with their origin. See the
655 .Sx Encryption
656 section for details.
657 .It Sy filesystem_count
658 The total number of filesystems and volumes that exist under this location in
659 the dataset tree.
660 This value is only available when a
661 .Sy filesystem_limit
662 has been set somewhere in the tree under which the dataset resides.
663 .It Sy keystatus
664 Indicates if an encryption key is currently loaded into ZFS. The possible
665 values are
666 .Sy none ,
667 .Sy available ,
668 and
669 .Sy unavailable .
670 See
671 .Nm zfs Cm load-key
672 and
673 .Nm zfs Cm unload-key .
674 .It Sy guid
675 The 64 bit GUID of this dataset or bookmark which does not change over its
676 entire lifetime. When a snapshot is sent to another pool, the received
677 snapshot has the same GUID. Thus, the
678 .Sy guid
679 is suitable to identify a snapshot across pools.
680 .It Sy logicalreferenced
681 The amount of space that is
682 .Qq logically
683 accessible by this dataset.
684 See the
685 .Sy referenced
686 property.
687 The logical space ignores the effect of the
688 .Sy compression
689 and
690 .Sy copies
691 properties, giving a quantity closer to the amount of data that applications
692 see.
693 However, it does include space consumed by metadata.
694 .Pp
695 This property can also be referred to by its shortened column name,
696 .Sy lrefer .
697 .It Sy logicalused
698 The amount of space that is
699 .Qq logically
700 consumed by this dataset and all its descendents.
701 See the
702 .Sy used
703 property.
704 The logical space ignores the effect of the
705 .Sy compression
706 and
707 .Sy copies
708 properties, giving a quantity closer to the amount of data that applications
709 see.
710 However, it does include space consumed by metadata.
711 .Pp
712 This property can also be referred to by its shortened column name,
713 .Sy lused .
714 .It Sy mounted
715 For file systems, indicates whether the file system is currently mounted.
716 This property can be either
717 .Sy yes
718 or
719 .Sy no .
720 .It Sy objsetid
721 A unique identifier for this dataset within the pool. Unlike the dataset's
722 .Sy guid
723 , the
724 .Sy objsetid
725 of a dataset is not transferred to other pools when the snapshot is copied
726 with a send/receive operation.
727 The
728 .Sy objsetid
729 can be reused (for a new datatset) after the dataset is deleted.
730 .It Sy origin
731 For cloned file systems or volumes, the snapshot from which the clone was
732 created.
733 See also the
734 .Sy clones
735 property.
736 .It Sy receive_resume_token
737 For filesystems or volumes which have saved partially-completed state from
738 .Sy zfs receive -s ,
739 this opaque token can be provided to
740 .Sy zfs send -t
741 to resume and complete the
742 .Sy zfs receive .
743 .It Sy referenced
744 The amount of data that is accessible by this dataset, which may or may not be
745 shared with other datasets in the pool.
746 When a snapshot or clone is created, it initially references the same amount of
747 space as the file system or snapshot it was created from, since its contents are
748 identical.
749 .Pp
750 This property can also be referred to by its shortened column name,
751 .Sy refer .
752 .It Sy refcompressratio
753 The compression ratio achieved for the
754 .Sy referenced
755 space of this dataset, expressed as a multiplier.
756 See also the
757 .Sy compressratio
758 property.
759 .It Sy snapshot_count
760 The total number of snapshots that exist under this location in the dataset
761 tree.
762 This value is only available when a
763 .Sy snapshot_limit
764 has been set somewhere in the tree under which the dataset resides.
765 .It Sy type
766 The type of dataset:
767 .Sy filesystem ,
768 .Sy volume ,
769 or
770 .Sy snapshot .
771 .It Sy used
772 The amount of space consumed by this dataset and all its descendents.
773 This is the value that is checked against this dataset's quota and reservation.
774 The space used does not include this dataset's reservation, but does take into
775 account the reservations of any descendent datasets.
776 The amount of space that a dataset consumes from its parent, as well as the
777 amount of space that is freed if this dataset is recursively destroyed, is the
778 greater of its space used and its reservation.
779 .Pp
780 The used space of a snapshot
781 .Po see the
782 .Sx Snapshots
783 section
784 .Pc
785 is space that is referenced exclusively by this snapshot.
786 If this snapshot is destroyed, the amount of
787 .Sy used
788 space will be freed.
789 Space that is shared by multiple snapshots isn't accounted for in this metric.
790 When a snapshot is destroyed, space that was previously shared with this
791 snapshot can become unique to snapshots adjacent to it, thus changing the used
792 space of those snapshots.
793 The used space of the latest snapshot can also be affected by changes in the
794 file system.
795 Note that the
796 .Sy used
797 space of a snapshot is a subset of the
798 .Sy written
799 space of the snapshot.
800 .Pp
801 The amount of space used, available, or referenced does not take into account
802 pending changes.
803 Pending changes are generally accounted for within a few seconds.
804 Committing a change to a disk using
805 .Xr fsync 2
806 or
807 .Dv O_SYNC
808 does not necessarily guarantee that the space usage information is updated
809 immediately.
810 .It Sy usedby*
811 The
812 .Sy usedby*
813 properties decompose the
814 .Sy used
815 properties into the various reasons that space is used.
816 Specifically,
817 .Sy used No =
818 .Sy usedbychildren No +
819 .Sy usedbydataset No +
820 .Sy usedbyrefreservation No +
821 .Sy usedbysnapshots .
822 These properties are only available for datasets created on
823 .Nm zpool
824 .Qo version 13 Qc
825 pools.
826 .It Sy usedbychildren
827 The amount of space used by children of this dataset, which would be freed if
828 all the dataset's children were destroyed.
829 .It Sy usedbydataset
830 The amount of space used by this dataset itself, which would be freed if the
831 dataset were destroyed
832 .Po after first removing any
833 .Sy refreservation
834 and destroying any necessary snapshots or descendents
835 .Pc .
836 .It Sy usedbyrefreservation
837 The amount of space used by a
838 .Sy refreservation
839 set on this dataset, which would be freed if the
840 .Sy refreservation
841 was removed.
842 .It Sy usedbysnapshots
843 The amount of space consumed by snapshots of this dataset.
844 In particular, it is the amount of space that would be freed if all of this
845 dataset's snapshots were destroyed.
846 Note that this is not simply the sum of the snapshots'
847 .Sy used
848 properties because space can be shared by multiple snapshots.
849 .It Sy userused Ns @ Ns Em user
850 The amount of space consumed by the specified user in this dataset.
851 Space is charged to the owner of each file, as displayed by
852 .Nm ls Fl l .
853 The amount of space charged is displayed by
854 .Nm du
855 and
856 .Nm ls Fl s .
857 See the
858 .Nm zfs Cm userspace
859 subcommand for more information.
860 .Pp
861 Unprivileged users can access only their own space usage.
862 The root user, or a user who has been granted the
863 .Sy userused
864 privilege with
865 .Nm zfs Cm allow ,
866 can access everyone's usage.
867 .Pp
868 The
869 .Sy userused Ns @ Ns Em ...
870 properties are not displayed by
871 .Nm zfs Cm get Sy all .
872 The user's name must be appended after the @ symbol, using one of the following
873 forms:
874 .Bl -bullet -width ""
875 .It
876 .Em POSIX name
877 .Po for example,
878 .Sy joe
879 .Pc
880 .It
881 .Em POSIX numeric ID
882 .Po for example,
883 .Sy 789
884 .Pc
885 .It
886 .Em SID name
887 .Po for example,
888 .Sy joe.smith@mydomain
889 .Pc
890 .It
891 .Em SID numeric ID
892 .Po for example,
893 .Sy S-1-123-456-789
894 .Pc
895 .El
896 .Pp
897 Files created on Linux always have POSIX owners.
898 .It Sy userobjused Ns @ Ns Em user
899 The
900 .Sy userobjused
901 property is similar to
902 .Sy userused
903 but instead it counts the number of objects consumed by a user. This property
904 counts all objects allocated on behalf of the user, it may differ from the
905 results of system tools such as
906 .Nm df Fl i .
907 .Pp
908 When the property
909 .Sy xattr=on
910 is set on a file system additional objects will be created per-file to store
911 extended attributes. These additional objects are reflected in the
912 .Sy userobjused
913 value and are counted against the user's
914 .Sy userobjquota .
915 When a file system is configured to use
916 .Sy xattr=sa
917 no additional internal objects are normally required.
918 .It Sy userrefs
919 This property is set to the number of user holds on this snapshot.
920 User holds are set by using the
921 .Nm zfs Cm hold
922 command.
923 .It Sy groupused Ns @ Ns Em group
924 The amount of space consumed by the specified group in this dataset.
925 Space is charged to the group of each file, as displayed by
926 .Nm ls Fl l .
927 See the
928 .Sy userused Ns @ Ns Em user
929 property for more information.
930 .Pp
931 Unprivileged users can only access their own groups' space usage.
932 The root user, or a user who has been granted the
933 .Sy groupused
934 privilege with
935 .Nm zfs Cm allow ,
936 can access all groups' usage.
937 .It Sy groupobjused Ns @ Ns Em group
938 The number of objects consumed by the specified group in this dataset.
939 Multiple objects may be charged to the group for each file when extended
940 attributes are in use. See the
941 .Sy userobjused Ns @ Ns Em user
942 property for more information.
943 .Pp
944 Unprivileged users can only access their own groups' space usage.
945 The root user, or a user who has been granted the
946 .Sy groupobjused
947 privilege with
948 .Nm zfs Cm allow ,
949 can access all groups' usage.
950 .It Sy projectused Ns @ Ns Em project
951 The amount of space consumed by the specified project in this dataset. Project
952 is identified via the project identifier (ID) that is object-based numeral
953 attribute. An object can inherit the project ID from its parent object (if the
954 parent has the flag of inherit project ID that can be set and changed via
955 .Nm chattr Fl /+P
956 or
957 .Nm zfs project Fl s )
958 when being created. The privileged user can set and change object's project
959 ID via
960 .Nm chattr Fl p
961 or
962 .Nm zfs project Fl s
963 anytime. Space is charged to the project of each file, as displayed by
964 .Nm lsattr Fl p
965 or
966 .Nm zfs project .
967 See the
968 .Sy userused Ns @ Ns Em user
969 property for more information.
970 .Pp
971 The root user, or a user who has been granted the
972 .Sy projectused
973 privilege with
974 .Nm zfs allow ,
975 can access all projects' usage.
976 .It Sy projectobjused Ns @ Ns Em project
977 The
978 .Sy projectobjused
979 is similar to
980 .Sy projectused
981 but instead it counts the number of objects consumed by project. When the
982 property
983 .Sy xattr=on
984 is set on a fileset, ZFS will create additional objects per-file to store
985 extended attributes. These additional objects are reflected in the
986 .Sy projectobjused
987 value and are counted against the project's
988 .Sy projectobjquota .
989 When a filesystem is configured to use
990 .Sy xattr=sa
991 no additional internal objects are required. See the
992 .Sy userobjused Ns @ Ns Em user
993 property for more information.
994 .Pp
995 The root user, or a user who has been granted the
996 .Sy projectobjused
997 privilege with
998 .Nm zfs allow ,
999 can access all projects' objects usage.
1000 .It Sy volblocksize
1001 For volumes, specifies the block size of the volume.
1002 The
1003 .Sy blocksize
1004 cannot be changed once the volume has been written, so it should be set at
1005 volume creation time.
1006 The default
1007 .Sy blocksize
1008 for volumes is 8 Kbytes.
1009 Any power of 2 from 512 bytes to 128 Kbytes is valid.
1010 .Pp
1011 This property can also be referred to by its shortened column name,
1012 .Sy volblock .
1013 .It Sy written
1014 The amount of space
1015 .Sy referenced
1016 by this dataset, that was written since the previous snapshot
1017 .Pq i.e. that is not referenced by the previous snapshot .
1018 .It Sy written Ns @ Ns Em snapshot
1019 The amount of
1020 .Sy referenced
1021 space written to this dataset since the specified snapshot.
1022 This is the space that is referenced by this dataset but was not referenced by
1023 the specified snapshot.
1024 .Pp
1025 The
1026 .Em snapshot
1027 may be specified as a short snapshot name
1028 .Po just the part after the
1029 .Sy @
1030 .Pc ,
1031 in which case it will be interpreted as a snapshot in the same filesystem as
1032 this dataset.
1033 The
1034 .Em snapshot
1035 may be a full snapshot name
1036 .Po Em filesystem Ns @ Ns Em snapshot Pc ,
1037 which for clones may be a snapshot in the origin's filesystem
1038 .Pq or the origin of the origin's filesystem, etc.
1039 .El
1040 .Pp
1041 The following native properties can be used to change the behavior of a ZFS
1042 dataset.
1043 .Bl -tag -width ""
1044 .It Xo
1045 .Sy aclinherit Ns = Ns Sy discard Ns | Ns Sy noallow Ns | Ns
1046 .Sy restricted Ns | Ns Sy passthrough Ns | Ns Sy passthrough-x
1047 .Xc
1048 Controls how ACEs are inherited when files and directories are created.
1049 .Bl -tag -width "passthrough-x"
1050 .It Sy discard
1051 does not inherit any ACEs.
1052 .It Sy noallow
1053 only inherits inheritable ACEs that specify
1054 .Qq deny
1055 permissions.
1056 .It Sy restricted
1057 default, removes the
1058 .Sy write_acl
1059 and
1060 .Sy write_owner
1061 permissions when the ACE is inherited.
1062 .It Sy passthrough
1063 inherits all inheritable ACEs without any modifications.
1064 .It Sy passthrough-x
1065 same meaning as
1066 .Sy passthrough ,
1067 except that the
1068 .Sy owner@ ,
1069 .Sy group@ ,
1070 and
1071 .Sy everyone@
1072 ACEs inherit the execute permission only if the file creation mode also requests
1073 the execute bit.
1074 .El
1075 .Pp
1076 When the property value is set to
1077 .Sy passthrough ,
1078 files are created with a mode determined by the inheritable ACEs.
1079 If no inheritable ACEs exist that affect the mode, then the mode is set in
1080 accordance to the requested mode from the application.
1081 .Pp
1082 The
1083 .Sy aclinherit
1084 property does not apply to POSIX ACLs.
1085 .It Sy acltype Ns = Ns Sy off Ns | Ns Sy noacl Ns | Ns Sy posixacl
1086 Controls whether ACLs are enabled and if so what type of ACL to use.
1087 .Bl -tag -width "posixacl"
1088 .It Sy off
1089 default, when a file system has the
1090 .Sy acltype
1091 property set to off then ACLs are disabled.
1092 .It Sy noacl
1093 an alias for
1094 .Sy off
1095 .It Sy posixacl
1096 indicates POSIX ACLs should be used. POSIX ACLs are specific to Linux and are
1097 not functional on other platforms. POSIX ACLs are stored as an extended
1098 attribute and therefore will not overwrite any existing NFSv4 ACLs which
1099 may be set.
1100 .El
1101 .Pp
1102 To obtain the best performance when setting
1103 .Sy posixacl
1104 users are strongly encouraged to set the
1105 .Sy xattr=sa
1106 property. This will result in the POSIX ACL being stored more efficiently on
1107 disk. But as a consequence, all new extended attributes will only be
1108 accessible from OpenZFS implementations which support the
1109 .Sy xattr=sa
1110 property. See the
1111 .Sy xattr
1112 property for more details.
1113 .It Sy atime Ns = Ns Sy on Ns | Ns Sy off
1114 Controls whether the access time for files is updated when they are read.
1115 Turning this property off avoids producing write traffic when reading files and
1116 can result in significant performance gains, though it might confuse mailers
1117 and other similar utilities. The values
1118 .Sy on
1119 and
1120 .Sy off
1121 are equivalent to the
1122 .Sy atime
1123 and
1124 .Sy noatime
1125 mount options. The default value is
1126 .Sy on .
1127 See also
1128 .Sy relatime
1129 below.
1130 .It Sy canmount Ns = Ns Sy on Ns | Ns Sy off Ns | Ns Sy noauto
1131 If this property is set to
1132 .Sy off ,
1133 the file system cannot be mounted, and is ignored by
1134 .Nm zfs Cm mount Fl a .
1135 Setting this property to
1136 .Sy off
1137 is similar to setting the
1138 .Sy mountpoint
1139 property to
1140 .Sy none ,
1141 except that the dataset still has a normal
1142 .Sy mountpoint
1143 property, which can be inherited.
1144 Setting this property to
1145 .Sy off
1146 allows datasets to be used solely as a mechanism to inherit properties.
1147 One example of setting
1148 .Sy canmount Ns = Ns Sy off
1149 is to have two datasets with the same
1150 .Sy mountpoint ,
1151 so that the children of both datasets appear in the same directory, but might
1152 have different inherited characteristics.
1153 .Pp
1154 When set to
1155 .Sy noauto ,
1156 a dataset can only be mounted and unmounted explicitly.
1157 The dataset is not mounted automatically when the dataset is created or
1158 imported, nor is it mounted by the
1159 .Nm zfs Cm mount Fl a
1160 command or unmounted by the
1161 .Nm zfs Cm unmount Fl a
1162 command.
1163 .Pp
1164 This property is not inherited.
1165 .It Xo
1166 .Sy checksum Ns = Ns Sy on Ns | Ns Sy off Ns | Ns Sy fletcher2 Ns | Ns
1167 .Sy fletcher4 Ns | Ns Sy sha256 Ns | Ns Sy noparity Ns | Ns
1168 .Sy sha512 Ns | Ns Sy skein Ns | Ns Sy edonr
1169 .Xc
1170 Controls the checksum used to verify data integrity.
1171 The default value is
1172 .Sy on ,
1173 which automatically selects an appropriate algorithm
1174 .Po currently,
1175 .Sy fletcher4 ,
1176 but this may change in future releases
1177 .Pc .
1178 The value
1179 .Sy off
1180 disables integrity checking on user data.
1181 The value
1182 .Sy noparity
1183 not only disables integrity but also disables maintaining parity for user data.
1184 This setting is used internally by a dump device residing on a RAID-Z pool and
1185 should not be used by any other dataset.
1186 Disabling checksums is
1187 .Sy NOT
1188 a recommended practice.
1189 .Pp
1190 The
1191 .Sy sha512 ,
1192 .Sy skein ,
1193 and
1194 .Sy edonr
1195 checksum algorithms require enabling the appropriate features on the pool.
1196 These pool features are not supported by GRUB and must not be used on the
1197 pool if GRUB needs to access the pool (e.g. for /boot).
1198 .Pp
1199 Please see
1200 .Xr zpool-features 5
1201 for more information on these algorithms.
1202 .Pp
1203 Changing this property affects only newly-written data.
1204 .It Xo
1205 .Sy compression Ns = Ns Sy on Ns | Ns Sy off Ns | Ns Sy gzip Ns | Ns
1206 .Sy gzip- Ns Em N Ns | Ns Sy lz4 Ns | Ns Sy lzjb Ns | Ns Sy zle
1207 .Xc
1208 Controls the compression algorithm used for this dataset.
1209 .Pp
1210 Setting compression to
1211 .Sy on
1212 indicates that the current default compression algorithm should be used.
1213 The default balances compression and decompression speed, with compression ratio
1214 and is expected to work well on a wide variety of workloads.
1215 Unlike all other settings for this property,
1216 .Sy on
1217 does not select a fixed compression type.
1218 As new compression algorithms are added to ZFS and enabled on a pool, the
1219 default compression algorithm may change.
1220 The current default compression algorithm is either
1221 .Sy lzjb
1222 or, if the
1223 .Sy lz4_compress
1224 feature is enabled,
1225 .Sy lz4 .
1226 .Pp
1227 The
1228 .Sy lz4
1229 compression algorithm is a high-performance replacement for the
1230 .Sy lzjb
1231 algorithm.
1232 It features significantly faster compression and decompression, as well as a
1233 moderately higher compression ratio than
1234 .Sy lzjb ,
1235 but can only be used on pools with the
1236 .Sy lz4_compress
1237 feature set to
1238 .Sy enabled .
1239 See
1240 .Xr zpool-features 5
1241 for details on ZFS feature flags and the
1242 .Sy lz4_compress
1243 feature.
1244 .Pp
1245 The
1246 .Sy lzjb
1247 compression algorithm is optimized for performance while providing decent data
1248 compression.
1249 .Pp
1250 The
1251 .Sy gzip
1252 compression algorithm uses the same compression as the
1253 .Xr gzip 1
1254 command.
1255 You can specify the
1256 .Sy gzip
1257 level by using the value
1258 .Sy gzip- Ns Em N ,
1259 where
1260 .Em N
1261 is an integer from 1
1262 .Pq fastest
1263 to 9
1264 .Pq best compression ratio .
1265 Currently,
1266 .Sy gzip
1267 is equivalent to
1268 .Sy gzip-6
1269 .Po which is also the default for
1270 .Xr gzip 1
1271 .Pc .
1272 .Pp
1273 The
1274 .Sy zle
1275 compression algorithm compresses runs of zeros.
1276 .Pp
1277 This property can also be referred to by its shortened column name
1278 .Sy compress .
1279 Changing this property affects only newly-written data.
1280 .Pp
1281 When any setting except
1282 .Sy off
1283 is selected, compression will explicitly check for blocks consisting of only
1284 zeroes (the NUL byte). When a zero-filled block is detected, it is stored as
1285 a hole and not compressed using the indicated compression algorithm.
1286 .Pp
1287 Any block being compressed must be no larger than 7/8 of its original size
1288 after compression, otherwise the compression will not be considered worthwhile
1289 and the block saved uncompressed. Note that when the logical block is less than
1290 8 times the disk sector size this effectively reduces the necessary compression
1291 ratio; for example 8k blocks on disks with 4k disk sectors must compress to 1/2
1292 or less of their original size.
1293 .It Xo
1294 .Sy context Ns = Ns Sy none Ns | Ns
1295 .Em SELinux_User:SElinux_Role:Selinux_Type:Sensitivity_Level
1296 .Xc
1297 This flag sets the SELinux context for all files in the file system under
1298 a mount point for that file system. See
1299 .Xr selinux 8
1300 for more information.
1301 .It Xo
1302 .Sy fscontext Ns = Ns Sy none Ns | Ns
1303 .Em SELinux_User:SElinux_Role:Selinux_Type:Sensitivity_Level
1304 .Xc
1305 This flag sets the SELinux context for the file system file system being
1306 mounted. See
1307 .Xr selinux 8
1308 for more information.
1309 .It Xo
1310 .Sy defcontext Ns = Ns Sy none Ns | Ns
1311 .Em SELinux_User:SElinux_Role:Selinux_Type:Sensitivity_Level
1312 .Xc
1313 This flag sets the SELinux default context for unlabeled files. See
1314 .Xr selinux 8
1315 for more information.
1316 .It Xo
1317 .Sy rootcontext Ns = Ns Sy none Ns | Ns
1318 .Em SELinux_User:SElinux_Role:Selinux_Type:Sensitivity_Level
1319 .Xc
1320 This flag sets the SELinux context for the root inode of the file system. See
1321 .Xr selinux 8
1322 for more information.
1323 .It Sy copies Ns = Ns Sy 1 Ns | Ns Sy 2 Ns | Ns Sy 3
1324 Controls the number of copies of data stored for this dataset.
1325 These copies are in addition to any redundancy provided by the pool, for
1326 example, mirroring or RAID-Z.
1327 The copies are stored on different disks, if possible.
1328 The space used by multiple copies is charged to the associated file and dataset,
1329 changing the
1330 .Sy used
1331 property and counting against quotas and reservations.
1332 .Pp
1333 Changing this property only affects newly-written data.
1334 Therefore, set this property at file system creation time by using the
1335 .Fl o Sy copies Ns = Ns Ar N
1336 option.
1337 .Pp
1338 Remember that ZFS will not import a pool with a missing top-level vdev. Do
1339 .Sy NOT
1340 create, for example a two-disk striped pool and set
1341 .Sy copies=2
1342 on some datasets thinking you have setup redundancy for them. When a disk
1343 fails you will not be able to import the pool and will have lost all of your
1344 data.
1345 .Pp
1346 Encrypted datasets may not have
1347 .Sy copies Ns = Ns Em 3
1348 since the implementation stores some encryption metadata where the third copy
1349 would normally be.
1350 .It Sy devices Ns = Ns Sy on Ns | Ns Sy off
1351 Controls whether device nodes can be opened on this file system.
1352 The default value is
1353 .Sy on .
1354 The values
1355 .Sy on
1356 and
1357 .Sy off
1358 are equivalent to the
1359 .Sy dev
1360 and
1361 .Sy nodev
1362 mount options.
1363 .It Xo
1364 .Sy dedup Ns = Ns Sy off Ns | Ns Sy on Ns | Ns Sy verify Ns | Ns
1365 .Sy sha256[,verify] Ns | Ns Sy sha512[,verify] Ns | Ns Sy skein[,verify] Ns | Ns
1366 .Sy edonr,verify
1367 .Xc
1368 Configures deduplication for a dataset. The default value is
1369 .Sy off .
1370 The default deduplication checksum is
1371 .Sy sha256
1372 (this may change in the future). When
1373 .Sy dedup
1374 is enabled, the checksum defined here overrides the
1375 .Sy checksum
1376 property. Setting the value to
1377 .Sy verify
1378 has the same effect as the setting
1379 .Sy sha256,verify.
1380 .Pp
1381 If set to
1382 .Sy verify ,
1383 ZFS will do a byte-to-byte comparsion in case of two blocks having the same
1384 signature to make sure the block contents are identical. Specifying
1385 .Sy verify
1386 is mandatory for the
1387 .Sy edonr
1388 algorithm.
1389 .Pp
1390 Unless necessary, deduplication should NOT be enabled on a system. See
1391 .Sx Deduplication
1392 above.
1393 .It Xo
1394 .Sy dnodesize Ns = Ns Sy legacy Ns | Ns Sy auto Ns | Ns Sy 1k Ns | Ns
1395 .Sy 2k Ns | Ns Sy 4k Ns | Ns Sy 8k Ns | Ns Sy 16k
1396 .Xc
1397 Specifies a compatibility mode or literal value for the size of dnodes in the
1398 file system. The default value is
1399 .Sy legacy .
1400 Setting this property to a value other than
1401 .Sy legacy
1402 requires the large_dnode pool feature to be enabled.
1403 .Pp
1404 Consider setting
1405 .Sy dnodesize
1406 to
1407 .Sy auto
1408 if the dataset uses the
1409 .Sy xattr=sa
1410 property setting and the workload makes heavy use of extended attributes. This
1411 may be applicable to SELinux-enabled systems, Lustre servers, and Samba
1412 servers, for example. Literal values are supported for cases where the optimal
1413 size is known in advance and for performance testing.
1414 .Pp
1415 Leave
1416 .Sy dnodesize
1417 set to
1418 .Sy legacy
1419 if you need to receive a send stream of this dataset on a pool that doesn't
1420 enable the large_dnode feature, or if you need to import this pool on a system
1421 that doesn't support the large_dnode feature.
1422 .Pp
1423 This property can also be referred to by its shortened column name,
1424 .Sy dnsize .
1425 .It Xo
1426 .Sy encryption Ns = Ns Sy off Ns | Ns Sy on Ns | Ns Sy aes-128-ccm Ns | Ns
1427 .Sy aes-192-ccm Ns | Ns Sy aes-256-ccm Ns | Ns Sy aes-128-gcm Ns | Ns
1428 .Sy aes-192-gcm Ns | Ns Sy aes-256-gcm
1429 .Xc
1430 Controls the encryption cipher suite (block cipher, key length, and mode) used
1431 for this dataset. Requires the
1432 .Sy encryption
1433 feature to be enabled on the pool.
1434 Requires a
1435 .Sy keyformat
1436 to be set at dataset creation time.
1437 .Pp
1438 Selecting
1439 .Sy encryption Ns = Ns Sy on
1440 when creating a dataset indicates that the default encryption suite will be
1441 selected, which is currently
1442 .Sy aes-256-ccm .
1443 In order to provide consistent data protection, encryption must be specified at
1444 dataset creation time and it cannot be changed afterwards.
1445 .Pp
1446 For more details and caveats about encryption see the
1447 .Sy Encryption
1448 section.
1449 .It Sy keyformat Ns = Ns Sy raw Ns | Ns Sy hex Ns | Ns Sy passphrase
1450 Controls what format the user's encryption key will be provided as. This
1451 property is only set when the dataset is encrypted.
1452 .Pp
1453 Raw keys and hex keys must be 32 bytes long (regardless of the chosen
1454 encryption suite) and must be randomly generated. A raw key can be generated
1455 with the following command:
1456 .Bd -literal
1457 # dd if=/dev/urandom of=/path/to/output/key bs=32 count=1
1458 .Ed
1459 .Pp
1460 Passphrases must be between 8 and 512 bytes long and will be processed through
1461 PBKDF2 before being used (see the
1462 .Sy pbkdf2iters
1463 property). Even though the
1464 encryption suite cannot be changed after dataset creation, the keyformat can be
1465 with
1466 .Nm zfs Cm change-key .
1467 .It Xo
1468 .Sy keylocation Ns = Ns Sy prompt Ns | Ns Sy file:// Ns Em </absolute/file/path>
1469 .Xc
1470 Controls where the user's encryption key will be loaded from by default for
1471 commands such as
1472 .Nm zfs Cm load-key
1473 and
1474 .Nm zfs Cm mount Cm -l .
1475 This property is only set for encrypted datasets which are encryption roots. If
1476 unspecified, the default is
1477 .Sy prompt.
1478 .Pp
1479 Even though the encryption suite cannot be changed after dataset creation, the
1480 keylocation can be with either
1481 .Nm zfs Cm set
1482 or
1483 .Nm zfs Cm change-key .
1484 If
1485 .Sy prompt
1486 is selected ZFS will ask for the key at the command prompt when it is required
1487 to access the encrypted data (see
1488 .Nm zfs Cm load-key
1489 for details). This setting will also allow the key to be passed in via STDIN,
1490 but users should be careful not to place keys which should be kept secret on
1491 the command line. If a file URI is selected, the key will be loaded from the
1492 specified absolute file path.
1493 .It Sy pbkdf2iters Ns = Ns Ar iterations
1494 Controls the number of PBKDF2 iterations that a
1495 .Sy passphrase
1496 encryption key should be run through when processing it into an encryption key.
1497 This property is only defined when encryption is enabled and a keyformat of
1498 .Sy passphrase
1499 is selected. The goal of PBKDF2 is to significantly increase the
1500 computational difficulty needed to brute force a user's passphrase. This is
1501 accomplished by forcing the attacker to run each passphrase through a
1502 computationally expensive hashing function many times before they arrive at the
1503 resulting key. A user who actually knows the passphrase will only have to pay
1504 this cost once. As CPUs become better at processing, this number should be
1505 raised to ensure that a brute force attack is still not possible. The current
1506 default is
1507 .Sy 350000
1508 and the minimum is
1509 .Sy 100000 .
1510 This property may be changed with
1511 .Nm zfs Cm change-key .
1512 .It Sy exec Ns = Ns Sy on Ns | Ns Sy off
1513 Controls whether processes can be executed from within this file system.
1514 The default value is
1515 .Sy on .
1516 The values
1517 .Sy on
1518 and
1519 .Sy off
1520 are equivalent to the
1521 .Sy exec
1522 and
1523 .Sy noexec
1524 mount options.
1525 .It Sy filesystem_limit Ns = Ns Em count Ns | Ns Sy none
1526 Limits the number of filesystems and volumes that can exist under this point in
1527 the dataset tree.
1528 The limit is not enforced if the user is allowed to change the limit.
1529 Setting a
1530 .Sy filesystem_limit
1531 to
1532 .Sy on
1533 a descendent of a filesystem that already has a
1534 .Sy filesystem_limit
1535 does not override the ancestor's
1536 .Sy filesystem_limit ,
1537 but rather imposes an additional limit.
1538 This feature must be enabled to be used
1539 .Po see
1540 .Xr zpool-features 5
1541 .Pc .
1542 .It Sy special_small_blocks Ns = Ns Em size
1543 This value represents the threshold block size for including small file
1544 blocks into the special allocation class. Blocks smaller than or equal to this
1545 value will be assigned to the special allocation class while greater blocks
1546 will be assigned to the regular class. Valid values are zero or a power of two
1547 from 512B up to 128K. The default size is 0 which means no small file blocks
1548 will be allocated in the special class.
1549 .Pp
1550 Before setting this property, a special class vdev must be added to the
1551 pool. See
1552 .Xr zpool 8
1553 for more details on the special allocation class.
1554 .It Sy mountpoint Ns = Ns Pa path Ns | Ns Sy none Ns | Ns Sy legacy
1555 Controls the mount point used for this file system.
1556 See the
1557 .Sx Mount Points
1558 section for more information on how this property is used.
1559 .Pp
1560 When the
1561 .Sy mountpoint
1562 property is changed for a file system, the file system and any children that
1563 inherit the mount point are unmounted.
1564 If the new value is
1565 .Sy legacy ,
1566 then they remain unmounted.
1567 Otherwise, they are automatically remounted in the new location if the property
1568 was previously
1569 .Sy legacy
1570 or
1571 .Sy none ,
1572 or if they were mounted before the property was changed.
1573 In addition, any shared file systems are unshared and shared in the new
1574 location.
1575 .It Sy nbmand Ns = Ns Sy on Ns | Ns Sy off
1576 Controls whether the file system should be mounted with
1577 .Sy nbmand
1578 .Pq Non Blocking mandatory locks .
1579 This is used for SMB clients.
1580 Changes to this property only take effect when the file system is umounted and
1581 remounted.
1582 See
1583 .Xr mount 8
1584 for more information on
1585 .Sy nbmand
1586 mounts. This property is not used on Linux.
1587 .It Sy overlay Ns = Ns Sy off Ns | Ns Sy on
1588 Allow mounting on a busy directory or a directory which already contains
1589 files or directories. This is the default mount behavior for Linux file systems.
1590 For consistency with OpenZFS on other platforms overlay mounts are
1591 .Sy off
1592 by default. Set to
1593 .Sy on
1594 to enable overlay mounts.
1595 .It Sy primarycache Ns = Ns Sy all Ns | Ns Sy none Ns | Ns Sy metadata
1596 Controls what is cached in the primary cache
1597 .Pq ARC .
1598 If this property is set to
1599 .Sy all ,
1600 then both user data and metadata is cached.
1601 If this property is set to
1602 .Sy none ,
1603 then neither user data nor metadata is cached.
1604 If this property is set to
1605 .Sy metadata ,
1606 then only metadata is cached.
1607 The default value is
1608 .Sy all .
1609 .It Sy quota Ns = Ns Em size Ns | Ns Sy none
1610 Limits the amount of space a dataset and its descendents can consume.
1611 This property enforces a hard limit on the amount of space used.
1612 This includes all space consumed by descendents, including file systems and
1613 snapshots.
1614 Setting a quota on a descendent of a dataset that already has a quota does not
1615 override the ancestor's quota, but rather imposes an additional limit.
1616 .Pp
1617 Quotas cannot be set on volumes, as the
1618 .Sy volsize
1619 property acts as an implicit quota.
1620 .It Sy snapshot_limit Ns = Ns Em count Ns | Ns Sy none
1621 Limits the number of snapshots that can be created on a dataset and its
1622 descendents.
1623 Setting a
1624 .Sy snapshot_limit
1625 on a descendent of a dataset that already has a
1626 .Sy snapshot_limit
1627 does not override the ancestor's
1628 .Sy snapshot_limit ,
1629 but rather imposes an additional limit.
1630 The limit is not enforced if the user is allowed to change the limit.
1631 For example, this means that recursive snapshots taken from the global zone are
1632 counted against each delegated dataset within a zone.
1633 This feature must be enabled to be used
1634 .Po see
1635 .Xr zpool-features 5
1636 .Pc .
1637 .It Sy userquota@ Ns Em user Ns = Ns Em size Ns | Ns Sy none
1638 Limits the amount of space consumed by the specified user.
1639 User space consumption is identified by the
1640 .Sy userspace@ Ns Em user
1641 property.
1642 .Pp
1643 Enforcement of user quotas may be delayed by several seconds.
1644 This delay means that a user might exceed their quota before the system notices
1645 that they are over quota and begins to refuse additional writes with the
1646 .Er EDQUOT
1647 error message.
1648 See the
1649 .Nm zfs Cm userspace
1650 subcommand for more information.
1651 .Pp
1652 Unprivileged users can only access their own groups' space usage.
1653 The root user, or a user who has been granted the
1654 .Sy userquota
1655 privilege with
1656 .Nm zfs Cm allow ,
1657 can get and set everyone's quota.
1658 .Pp
1659 This property is not available on volumes, on file systems before version 4, or
1660 on pools before version 15.
1661 The
1662 .Sy userquota@ Ns Em ...
1663 properties are not displayed by
1664 .Nm zfs Cm get Sy all .
1665 The user's name must be appended after the
1666 .Sy @
1667 symbol, using one of the following forms:
1668 .Bl -bullet
1669 .It
1670 .Em POSIX name
1671 .Po for example,
1672 .Sy joe
1673 .Pc
1674 .It
1675 .Em POSIX numeric ID
1676 .Po for example,
1677 .Sy 789
1678 .Pc
1679 .It
1680 .Em SID name
1681 .Po for example,
1682 .Sy joe.smith@mydomain
1683 .Pc
1684 .It
1685 .Em SID numeric ID
1686 .Po for example,
1687 .Sy S-1-123-456-789
1688 .Pc
1689 .El
1690 .Pp
1691 Files created on Linux always have POSIX owners.
1692 .It Sy userobjquota@ Ns Em user Ns = Ns Em size Ns | Ns Sy none
1693 The
1694 .Sy userobjquota
1695 is similar to
1696 .Sy userquota
1697 but it limits the number of objects a user can create. Please refer to
1698 .Sy userobjused
1699 for more information about how objects are counted.
1700 .It Sy groupquota@ Ns Em group Ns = Ns Em size Ns | Ns Sy none
1701 Limits the amount of space consumed by the specified group.
1702 Group space consumption is identified by the
1703 .Sy groupused@ Ns Em group
1704 property.
1705 .Pp
1706 Unprivileged users can access only their own groups' space usage.
1707 The root user, or a user who has been granted the
1708 .Sy groupquota
1709 privilege with
1710 .Nm zfs Cm allow ,
1711 can get and set all groups' quotas.
1712 .It Sy groupobjquota@ Ns Em group Ns = Ns Em size Ns | Ns Sy none
1713 The
1714 .Sy groupobjquota
1715 is similar to
1716 .Sy groupquota
1717 but it limits number of objects a group can consume. Please refer to
1718 .Sy userobjused
1719 for more information about how objects are counted.
1720 .It Sy projectquota@ Ns Em project Ns = Ns Em size Ns | Ns Sy none
1721 Limits the amount of space consumed by the specified project. Project
1722 space consumption is identified by the
1723 .Sy projectused@ Ns Em project
1724 property. Please refer to
1725 .Sy projectused
1726 for more information about how project is identified and set/changed.
1727 .Pp
1728 The root user, or a user who has been granted the
1729 .Sy projectquota
1730 privilege with
1731 .Nm zfs allow ,
1732 can access all projects' quota.
1733 .It Sy projectobjquota@ Ns Em project Ns = Ns Em size Ns | Ns Sy none
1734 The
1735 .Sy projectobjquota
1736 is similar to
1737 .Sy projectquota
1738 but it limits number of objects a project can consume. Please refer to
1739 .Sy userobjused
1740 for more information about how objects are counted.
1741 .It Sy readonly Ns = Ns Sy on Ns | Ns Sy off
1742 Controls whether this dataset can be modified.
1743 The default value is
1744 .Sy off .
1745 The values
1746 .Sy on
1747 and
1748 .Sy off
1749 are equivalent to the
1750 .Sy ro
1751 and
1752 .Sy rw
1753 mount options.
1754 .Pp
1755 This property can also be referred to by its shortened column name,
1756 .Sy rdonly .
1757 .It Sy recordsize Ns = Ns Em size
1758 Specifies a suggested block size for files in the file system.
1759 This property is designed solely for use with database workloads that access
1760 files in fixed-size records.
1761 ZFS automatically tunes block sizes according to internal algorithms optimized
1762 for typical access patterns.
1763 .Pp
1764 For databases that create very large files but access them in small random
1765 chunks, these algorithms may be suboptimal.
1766 Specifying a
1767 .Sy recordsize
1768 greater than or equal to the record size of the database can result in
1769 significant performance gains.
1770 Use of this property for general purpose file systems is strongly discouraged,
1771 and may adversely affect performance.
1772 .Pp
1773 The size specified must be a power of two greater than or equal to 512 and less
1774 than or equal to 128 Kbytes.
1775 If the
1776 .Sy large_blocks
1777 feature is enabled on the pool, the size may be up to 1 Mbyte.
1778 See
1779 .Xr zpool-features 5
1780 for details on ZFS feature flags.
1781 .Pp
1782 Changing the file system's
1783 .Sy recordsize
1784 affects only files created afterward; existing files are unaffected.
1785 .Pp
1786 This property can also be referred to by its shortened column name,
1787 .Sy recsize .
1788 .It Sy redundant_metadata Ns = Ns Sy all Ns | Ns Sy most
1789 Controls what types of metadata are stored redundantly.
1790 ZFS stores an extra copy of metadata, so that if a single block is corrupted,
1791 the amount of user data lost is limited.
1792 This extra copy is in addition to any redundancy provided at the pool level
1793 .Pq e.g. by mirroring or RAID-Z ,
1794 and is in addition to an extra copy specified by the
1795 .Sy copies
1796 property
1797 .Pq up to a total of 3 copies .
1798 For example if the pool is mirrored,
1799 .Sy copies Ns = Ns 2 ,
1800 and
1801 .Sy redundant_metadata Ns = Ns Sy most ,
1802 then ZFS stores 6 copies of most metadata, and 4 copies of data and some
1803 metadata.
1804 .Pp
1805 When set to
1806 .Sy all ,
1807 ZFS stores an extra copy of all metadata.
1808 If a single on-disk block is corrupt, at worst a single block of user data
1809 .Po which is
1810 .Sy recordsize
1811 bytes long
1812 .Pc
1813 can be lost.
1814 .Pp
1815 When set to
1816 .Sy most ,
1817 ZFS stores an extra copy of most types of metadata.
1818 This can improve performance of random writes, because less metadata must be
1819 written.
1820 In practice, at worst about 100 blocks
1821 .Po of
1822 .Sy recordsize
1823 bytes each
1824 .Pc
1825 of user data can be lost if a single on-disk block is corrupt.
1826 The exact behavior of which metadata blocks are stored redundantly may change in
1827 future releases.
1828 .Pp
1829 The default value is
1830 .Sy all .
1831 .It Sy refquota Ns = Ns Em size Ns | Ns Sy none
1832 Limits the amount of space a dataset can consume.
1833 This property enforces a hard limit on the amount of space used.
1834 This hard limit does not include space used by descendents, including file
1835 systems and snapshots.
1836 .It Sy refreservation Ns = Ns Em size Ns | Ns Sy none Ns | Ns Sy auto
1837 The minimum amount of space guaranteed to a dataset, not including its
1838 descendents.
1839 When the amount of space used is below this value, the dataset is treated as if
1840 it were taking up the amount of space specified by
1841 .Sy refreservation .
1842 The
1843 .Sy refreservation
1844 reservation is accounted for in the parent datasets' space used, and counts
1845 against the parent datasets' quotas and reservations.
1846 .Pp
1847 If
1848 .Sy refreservation
1849 is set, a snapshot is only allowed if there is enough free pool space outside of
1850 this reservation to accommodate the current number of
1851 .Qq referenced
1852 bytes in the dataset.
1853 .Pp
1854 If
1855 .Sy refreservation
1856 is set to
1857 .Sy auto ,
1858 a volume is thick provisioned
1859 .Po or
1860 .Qq not sparse
1861 .Pc .
1862 .Sy refreservation Ns = Ns Sy auto
1863 is only supported on volumes.
1864 See
1865 .Sy volsize
1866 in the
1867 .Sx Native Properties
1868 section for more information about sparse volumes.
1869 .Pp
1870 This property can also be referred to by its shortened column name,
1871 .Sy refreserv .
1872 .It Sy relatime Ns = Ns Sy on Ns | Ns Sy off
1873 Controls the manner in which the access time is updated when
1874 .Sy atime=on
1875 is set. Turning this property on causes the access time to be updated relative
1876 to the modify or change time. Access time is only updated if the previous
1877 access time was earlier than the current modify or change time or if the
1878 existing access time hasn't been updated within the past 24 hours. The default
1879 value is
1880 .Sy off .
1881 The values
1882 .Sy on
1883 and
1884 .Sy off
1885 are equivalent to the
1886 .Sy relatime
1887 and
1888 .Sy norelatime
1889 mount options.
1890 .It Sy reservation Ns = Ns Em size Ns | Ns Sy none
1891 The minimum amount of space guaranteed to a dataset and its descendants.
1892 When the amount of space used is below this value, the dataset is treated as if
1893 it were taking up the amount of space specified by its reservation.
1894 Reservations are accounted for in the parent datasets' space used, and count
1895 against the parent datasets' quotas and reservations.
1896 .Pp
1897 This property can also be referred to by its shortened column name,
1898 .Sy reserv .
1899 .It Sy secondarycache Ns = Ns Sy all Ns | Ns Sy none Ns | Ns Sy metadata
1900 Controls what is cached in the secondary cache
1901 .Pq L2ARC .
1902 If this property is set to
1903 .Sy all ,
1904 then both user data and metadata is cached.
1905 If this property is set to
1906 .Sy none ,
1907 then neither user data nor metadata is cached.
1908 If this property is set to
1909 .Sy metadata ,
1910 then only metadata is cached.
1911 The default value is
1912 .Sy all .
1913 .It Sy setuid Ns = Ns Sy on Ns | Ns Sy off
1914 Controls whether the setuid bit is respected for the file system.
1915 The default value is
1916 .Sy on .
1917 The values
1918 .Sy on
1919 and
1920 .Sy off
1921 are equivalent to the
1922 .Sy suid
1923 and
1924 .Sy nosuid
1925 mount options.
1926 .It Sy sharesmb Ns = Ns Sy on Ns | Ns Sy off Ns | Ns Em opts
1927 Controls whether the file system is shared by using
1928 .Sy Samba USERSHARES
1929 and what options are to be used. Otherwise, the file system is automatically
1930 shared and unshared with the
1931 .Nm zfs Cm share
1932 and
1933 .Nm zfs Cm unshare
1934 commands. If the property is set to on, the
1935 .Xr net 8
1936 command is invoked to create a
1937 .Sy USERSHARE .
1938 .Pp
1939 Because SMB shares requires a resource name, a unique resource name is
1940 constructed from the dataset name. The constructed name is a copy of the
1941 dataset name except that the characters in the dataset name, which would be
1942 invalid in the resource name, are replaced with underscore (_) characters.
1943 Linux does not currently support additional options which might be available
1944 on Solaris.
1945 .Pp
1946 If the
1947 .Sy sharesmb
1948 property is set to
1949 .Sy off ,
1950 the file systems are unshared.
1951 .Pp
1952 The share is created with the ACL (Access Control List) "Everyone:F" ("F"
1953 stands for "full permissions", ie. read and write permissions) and no guest
1954 access (which means Samba must be able to authenticate a real user, system
1955 passwd/shadow, LDAP or smbpasswd based) by default. This means that any
1956 additional access control (disallow specific user specific access etc) must
1957 be done on the underlying file system.
1958 .It Sy sharenfs Ns = Ns Sy on Ns | Ns Sy off Ns | Ns Em opts
1959 Controls whether the file system is shared via NFS, and what options are to be
1960 used.
1961 A file system with a
1962 .Sy sharenfs
1963 property of
1964 .Sy off
1965 is managed with the
1966 .Xr exportfs 8
1967 command and entries in the
1968 .Em /etc/exports
1969 file.
1970 Otherwise, the file system is automatically shared and unshared with the
1971 .Nm zfs Cm share
1972 and
1973 .Nm zfs Cm unshare
1974 commands.
1975 If the property is set to
1976 .Sy on ,
1977 the dataset is shared using the default options:
1978 .Pp
1979 .Em sec=sys,rw,crossmnt,no_subtree_check,no_root_squash
1980 .Pp
1981 See
1982 .Xr exports 5
1983 for the meaning of the default options. Otherwise, the
1984 .Xr exportfs 8
1985 command is invoked with options equivalent to the contents of this property.
1986 .Pp
1987 When the
1988 .Sy sharenfs
1989 property is changed for a dataset, the dataset and any children inheriting the
1990 property are re-shared with the new options, only if the property was previously
1991 .Sy off ,
1992 or if they were shared before the property was changed.
1993 If the new property is
1994 .Sy off ,
1995 the file systems are unshared.
1996 .It Sy logbias Ns = Ns Sy latency Ns | Ns Sy throughput
1997 Provide a hint to ZFS about handling of synchronous requests in this dataset.
1998 If
1999 .Sy logbias
2000 is set to
2001 .Sy latency
2002 .Pq the default ,
2003 ZFS will use pool log devices
2004 .Pq if configured
2005 to handle the requests at low latency.
2006 If
2007 .Sy logbias
2008 is set to
2009 .Sy throughput ,
2010 ZFS will not use configured pool log devices.
2011 ZFS will instead optimize synchronous operations for global pool throughput and
2012 efficient use of resources.
2013 .It Sy snapdev Ns = Ns Sy hidden Ns | Ns Sy visible
2014 Controls whether the volume snapshot devices under
2015 .Em /dev/zvol/<pool>
2016 are hidden or visible. The default value is
2017 .Sy hidden .
2018 .It Sy snapdir Ns = Ns Sy hidden Ns | Ns Sy visible
2019 Controls whether the
2020 .Pa .zfs
2021 directory is hidden or visible in the root of the file system as discussed in
2022 the
2023 .Sx Snapshots
2024 section.
2025 The default value is
2026 .Sy hidden .
2027 .It Sy sync Ns = Ns Sy standard Ns | Ns Sy always Ns | Ns Sy disabled
2028 Controls the behavior of synchronous requests
2029 .Pq e.g. fsync, O_DSYNC .
2030 .Sy standard
2031 is the
2032 .Tn POSIX
2033 specified behavior of ensuring all synchronous requests are written to stable
2034 storage and all devices are flushed to ensure data is not cached by device
2035 controllers
2036 .Pq this is the default .
2037 .Sy always
2038 causes every file system transaction to be written and flushed before its
2039 system call returns.
2040 This has a large performance penalty.
2041 .Sy disabled
2042 disables synchronous requests.
2043 File system transactions are only committed to stable storage periodically.
2044 This option will give the highest performance.
2045 However, it is very dangerous as ZFS would be ignoring the synchronous
2046 transaction demands of applications such as databases or NFS.
2047 Administrators should only use this option when the risks are understood.
2048 .It Sy version Ns = Ns Em N Ns | Ns Sy current
2049 The on-disk version of this file system, which is independent of the pool
2050 version.
2051 This property can only be set to later supported versions.
2052 See the
2053 .Nm zfs Cm upgrade
2054 command.
2055 .It Sy volsize Ns = Ns Em size
2056 For volumes, specifies the logical size of the volume.
2057 By default, creating a volume establishes a reservation of equal size.
2058 For storage pools with a version number of 9 or higher, a
2059 .Sy refreservation
2060 is set instead.
2061 Any changes to
2062 .Sy volsize
2063 are reflected in an equivalent change to the reservation
2064 .Po or
2065 .Sy refreservation
2066 .Pc .
2067 The
2068 .Sy volsize
2069 can only be set to a multiple of
2070 .Sy volblocksize ,
2071 and cannot be zero.
2072 .Pp
2073 The reservation is kept equal to the volume's logical size to prevent unexpected
2074 behavior for consumers.
2075 Without the reservation, the volume could run out of space, resulting in
2076 undefined behavior or data corruption, depending on how the volume is used.
2077 These effects can also occur when the volume size is changed while it is in use
2078 .Pq particularly when shrinking the size .
2079 Extreme care should be used when adjusting the volume size.
2080 .Pp
2081 Though not recommended, a
2082 .Qq sparse volume
2083 .Po also known as
2084 .Qq thin provisioned
2085 .Pc
2086 can be created by specifying the
2087 .Fl s
2088 option to the
2089 .Nm zfs Cm create Fl V
2090 command, or by changing the value of the
2091 .Sy refreservation
2092 property
2093 .Po or
2094 .Sy reservation
2095 property on pool version 8 or earlier
2096 .Pc
2097 after the volume has been created.
2098 A
2099 .Qq sparse volume
2100 is a volume where the value of
2101 .Sy refreservation
2102 is less than the size of the volume plus the space required to store its
2103 metadata.
2104 Consequently, writes to a sparse volume can fail with
2105 .Er ENOSPC
2106 when the pool is low on space.
2107 For a sparse volume, changes to
2108 .Sy volsize
2109 are not reflected in the
2110 .Sy refreservation.
2111 A volume that is not sparse is said to be
2112 .Qq thick provisioned .
2113 A sparse volume can become thick provisioned by setting
2114 .Sy refreservation
2115 to
2116 .Sy auto .
2117 .It Sy volmode Ns = Ns Cm default | full | geom | dev | none
2118 This property specifies how volumes should be exposed to the OS.
2119 Setting it to
2120 .Sy full
2121 exposes volumes as fully fledged block devices, providing maximal
2122 functionality. The value
2123 .Sy geom
2124 is just an alias for
2125 .Sy full
2126 and is kept for compatibility.
2127 Setting it to
2128 .Sy dev
2129 hides its partitions.
2130 Volumes with property set to
2131 .Sy none
2132 are not exposed outside ZFS, but can be snapshoted, cloned, replicated, etc,
2133 that can be suitable for backup purposes.
2134 Value
2135 .Sy default
2136 means that volumes exposition is controlled by system-wide tunable
2137 .Va zvol_volmode ,
2138 where
2139 .Sy full ,
2140 .Sy dev
2141 and
2142 .Sy none
2143 are encoded as 1, 2 and 3 respectively.
2144 The default values is
2145 .Sy full .
2146 .It Sy vscan Ns = Ns Sy on Ns | Ns Sy off
2147 Controls whether regular files should be scanned for viruses when a file is
2148 opened and closed.
2149 In addition to enabling this property, the virus scan service must also be
2150 enabled for virus scanning to occur.
2151 The default value is
2152 .Sy off .
2153 This property is not used on Linux.
2154 .It Sy xattr Ns = Ns Sy on Ns | Ns Sy off Ns | Ns Sy sa
2155 Controls whether extended attributes are enabled for this file system. Two
2156 styles of extended attributes are supported either directory based or system
2157 attribute based.
2158 .Pp
2159 The default value of
2160 .Sy on
2161 enables directory based extended attributes. This style of extended attribute
2162 imposes no practical limit on either the size or number of attributes which
2163 can be set on a file. Although under Linux the
2164 .Xr getxattr 2
2165 and
2166 .Xr setxattr 2
2167 system calls limit the maximum size to 64K. This is the most compatible
2168 style of extended attribute and is supported by all OpenZFS implementations.
2169 .Pp
2170 System attribute based xattrs can be enabled by setting the value to
2171 .Sy sa .
2172 The key advantage of this type of xattr is improved performance. Storing
2173 extended attributes as system attributes significantly decreases the amount of
2174 disk IO required. Up to 64K of data may be stored per-file in the space
2175 reserved for system attributes. If there is not enough space available for
2176 an extended attribute then it will be automatically written as a directory
2177 based xattr. System attribute based extended attributes are not accessible
2178 on platforms which do not support the
2179 .Sy xattr=sa
2180 feature.
2181 .Pp
2182 The use of system attribute based xattrs is strongly encouraged for users of
2183 SELinux or POSIX ACLs. Both of these features heavily rely of extended
2184 attributes and benefit significantly from the reduced access time.
2185 .Pp
2186 The values
2187 .Sy on
2188 and
2189 .Sy off
2190 are equivalent to the
2191 .Sy xattr
2192 and
2193 .Sy noxattr
2194 mount options.
2195 .It Sy zoned Ns = Ns Sy on Ns | Ns Sy off
2196 Controls whether the dataset is managed from a non-global zone. Zones are a
2197 Solaris feature and are not relevant on Linux. The default value is
2198 .Sy off .
2199 .El
2200 .Pp
2201 The following three properties cannot be changed after the file system is
2202 created, and therefore, should be set when the file system is created.
2203 If the properties are not set with the
2204 .Nm zfs Cm create
2205 or
2206 .Nm zpool Cm create
2207 commands, these properties are inherited from the parent dataset.
2208 If the parent dataset lacks these properties due to having been created prior to
2209 these features being supported, the new file system will have the default values
2210 for these properties.
2211 .Bl -tag -width ""
2212 .It Xo
2213 .Sy casesensitivity Ns = Ns Sy sensitive Ns | Ns
2214 .Sy insensitive Ns | Ns Sy mixed
2215 .Xc
2216 Indicates whether the file name matching algorithm used by the file system
2217 should be case-sensitive, case-insensitive, or allow a combination of both
2218 styles of matching.
2219 The default value for the
2220 .Sy casesensitivity
2221 property is
2222 .Sy sensitive .
2223 Traditionally,
2224 .Ux
2225 and
2226 .Tn POSIX
2227 file systems have case-sensitive file names.
2228 .Pp
2229 The
2230 .Sy mixed
2231 value for the
2232 .Sy casesensitivity
2233 property indicates that the file system can support requests for both
2234 case-sensitive and case-insensitive matching behavior.
2235 Currently, case-insensitive matching behavior on a file system that supports
2236 mixed behavior is limited to the SMB server product.
2237 For more information about the
2238 .Sy mixed
2239 value behavior, see the "ZFS Administration Guide".
2240 .It Xo
2241 .Sy normalization Ns = Ns Sy none Ns | Ns Sy formC Ns | Ns
2242 .Sy formD Ns | Ns Sy formKC Ns | Ns Sy formKD
2243 .Xc
2244 Indicates whether the file system should perform a
2245 .Sy unicode
2246 normalization of file names whenever two file names are compared, and which
2247 normalization algorithm should be used.
2248 File names are always stored unmodified, names are normalized as part of any
2249 comparison process.
2250 If this property is set to a legal value other than
2251 .Sy none ,
2252 and the
2253 .Sy utf8only
2254 property was left unspecified, the
2255 .Sy utf8only
2256 property is automatically set to
2257 .Sy on .
2258 The default value of the
2259 .Sy normalization
2260 property is
2261 .Sy none .
2262 This property cannot be changed after the file system is created.
2263 .It Sy utf8only Ns = Ns Sy on Ns | Ns Sy off
2264 Indicates whether the file system should reject file names that include
2265 characters that are not present in the
2266 .Sy UTF-8
2267 character code set.
2268 If this property is explicitly set to
2269 .Sy off ,
2270 the normalization property must either not be explicitly set or be set to
2271 .Sy none .
2272 The default value for the
2273 .Sy utf8only
2274 property is
2275 .Sy off .
2276 This property cannot be changed after the file system is created.
2277 .El
2278 .Pp
2279 The
2280 .Sy casesensitivity ,
2281 .Sy normalization ,
2282 and
2283 .Sy utf8only
2284 properties are also new permissions that can be assigned to non-privileged users
2285 by using the ZFS delegated administration feature.
2286 .Ss "Temporary Mount Point Properties"
2287 When a file system is mounted, either through
2288 .Xr mount 8
2289 for legacy mounts or the
2290 .Nm zfs Cm mount
2291 command for normal file systems, its mount options are set according to its
2292 properties.
2293 The correlation between properties and mount options is as follows:
2294 .Bd -literal
2295 PROPERTY MOUNT OPTION
2296 atime atime/noatime
2297 canmount auto/noauto
2298 devices dev/nodev
2299 exec exec/noexec
2300 readonly ro/rw
2301 relatime relatime/norelatime
2302 setuid suid/nosuid
2303 xattr xattr/noxattr
2304 .Ed
2305 .Pp
2306 In addition, these options can be set on a per-mount basis using the
2307 .Fl o
2308 option, without affecting the property that is stored on disk.
2309 The values specified on the command line override the values stored in the
2310 dataset.
2311 The
2312 .Sy nosuid
2313 option is an alias for
2314 .Sy nodevices Ns \&, Ns Sy nosetuid .
2315 These properties are reported as
2316 .Qq temporary
2317 by the
2318 .Nm zfs Cm get
2319 command.
2320 If the properties are changed while the dataset is mounted, the new setting
2321 overrides any temporary settings.
2322 .Ss "User Properties"
2323 In addition to the standard native properties, ZFS supports arbitrary user
2324 properties.
2325 User properties have no effect on ZFS behavior, but applications or
2326 administrators can use them to annotate datasets
2327 .Pq file systems, volumes, and snapshots .
2328 .Pp
2329 User property names must contain a colon
2330 .Pq Qq Sy \&:
2331 character to distinguish them from native properties.
2332 They may contain lowercase letters, numbers, and the following punctuation
2333 characters: colon
2334 .Pq Qq Sy \&: ,
2335 dash
2336 .Pq Qq Sy - ,
2337 period
2338 .Pq Qq Sy \&. ,
2339 and underscore
2340 .Pq Qq Sy _ .
2341 The expected convention is that the property name is divided into two portions
2342 such as
2343 .Em module Ns \&: Ns Em property ,
2344 but this namespace is not enforced by ZFS.
2345 User property names can be at most 256 characters, and cannot begin with a dash
2346 .Pq Qq Sy - .
2347 .Pp
2348 When making programmatic use of user properties, it is strongly suggested to use
2349 a reversed
2350 .Sy DNS
2351 domain name for the
2352 .Em module
2353 component of property names to reduce the chance that two
2354 independently-developed packages use the same property name for different
2355 purposes.
2356 .Pp
2357 The values of user properties are arbitrary strings, are always inherited, and
2358 are never validated.
2359 All of the commands that operate on properties
2360 .Po Nm zfs Cm list ,
2361 .Nm zfs Cm get ,
2362 .Nm zfs Cm set ,
2363 and so forth
2364 .Pc
2365 can be used to manipulate both native properties and user properties.
2366 Use the
2367 .Nm zfs Cm inherit
2368 command to clear a user property.
2369 If the property is not defined in any parent dataset, it is removed entirely.
2370 Property values are limited to 8192 bytes.
2371 .Ss ZFS Volumes as Swap
2372 ZFS volumes may be used as swap devices. After creating the volume with the
2373 .Nm zfs Cm create Fl V
2374 command set up and enable the swap area using the
2375 .Xr mkswap 8
2376 and
2377 .Xr swapon 8
2378 commands. Do not swap to a file on a ZFS file system. A ZFS swap file
2379 configuration is not supported.
2380 .Ss Encryption
2381 Enabling the
2382 .Sy encryption
2383 feature allows for the creation of encrypted filesystems and volumes. ZFS
2384 will encrypt file and zvol data, file attributes, ACLs, permission bits,
2385 directory listings, FUID mappings, and
2386 .Sy userused
2387 /
2388 .Sy groupused
2389 data. ZFS will not encrypt metadata related to the pool structure, including
2390 dataset and snapshot names, dataset hierarchy, properties, file size, file
2391 holes, and deduplication tables.
2392 .Pp
2393 Key rotation is managed by ZFS. Changing the user's key (e.g. a passphrase)
2394 does not require re-encrypting the entire dataset. Datasets can be scrubbed,
2395 resilvered, renamed, and deleted without the encryption keys being loaded (see the
2396 .Nm zfs Cm load-key
2397 subcommand for more info on key loading).
2398 .Pp
2399 Creating an encrypted dataset requires specifying the
2400 .Sy encryption
2401 and
2402 .Sy keyformat
2403 properties at creation time, along with an optional
2404 .Sy keylocation
2405 and
2406 .Sy pbkdf2iters .
2407 After entering an encryption key, the
2408 created dataset will become an encryption root. Any descendant datasets will
2409 inherit their encryption key from the encryption root by default, meaning that
2410 loading, unloading, or changing the key for the encryption root will implicitly
2411 do the same for all inheriting datasets. If this inheritance is not desired,
2412 simply supply a
2413 .Sy keyformat
2414 when creating the child dataset or use
2415 .Nm zfs Cm change-key
2416 to break an existing relationship, creating a new encryption root on the child.
2417 Note that the child's
2418 .Sy keyformat
2419 may match that of the parent while still creating a new encryption root, and
2420 that changing the
2421 .Sy encryption
2422 property alone does not create a new encryption root; this would simply use a
2423 different cipher suite with the same key as its encryption root. The one
2424 exception is that clones will always use their origin's encryption key.
2425 As a result of this exception, some encryption-related properties (namely
2426 .Sy keystatus ,
2427 .Sy keyformat ,
2428 .Sy keylocation ,
2429 and
2430 .Sy pbkdf2iters )
2431 do not inherit like other ZFS properties and instead use the value determined
2432 by their encryption root. Encryption root inheritance can be tracked via the
2433 read-only
2434 .Sy encryptionroot
2435 property.
2436 .Pp
2437 Encryption changes the behavior of a few ZFS
2438 operations. Encryption is applied after compression so compression ratios are
2439 preserved. Normally checksums in ZFS are 256 bits long, but for encrypted data
2440 the checksum is 128 bits of the user-chosen checksum and 128 bits of MAC from
2441 the encryption suite, which provides additional protection against maliciously
2442 altered data. Deduplication is still possible with encryption enabled but for
2443 security, datasets will only dedup against themselves, their snapshots, and
2444 their clones.
2445 .Pp
2446 There are a few limitations on encrypted datasets. Encrypted data cannot be
2447 embedded via the
2448 .Sy embedded_data
2449 feature. Encrypted datasets may not have
2450 .Sy copies Ns = Ns Em 3
2451 since the implementation stores some encryption metadata where the third copy
2452 would normally be. Since compression is applied before encryption datasets may
2453 be vulnerable to a CRIME-like attack if applications accessing the data allow
2454 for it. Deduplication with encryption will leak information about which blocks
2455 are equivalent in a dataset and will incur an extra CPU cost per block written.
2456 .Sh SUBCOMMANDS
2457 All subcommands that modify state are logged persistently to the pool in their
2458 original form.
2459 .Bl -tag -width ""
2460 .It Nm Fl ?
2461 Displays a help message.
2462 .It Xo
2463 .Nm
2464 .Fl V, -version
2465 .Xc
2466 An alias for the
2467 .Nm zfs Cm version
2468 subcommand.
2469 .It Xo
2470 .Nm
2471 .Cm create
2472 .Op Fl p
2473 .Oo Fl o Ar property Ns = Ns Ar value Oc Ns ...
2474 .Ar filesystem
2475 .Xc
2476 Creates a new ZFS file system.
2477 The file system is automatically mounted according to the
2478 .Sy mountpoint
2479 property inherited from the parent.
2480 .Bl -tag -width "-o"
2481 .It Fl o Ar property Ns = Ns Ar value
2482 Sets the specified property as if the command
2483 .Nm zfs Cm set Ar property Ns = Ns Ar value
2484 was invoked at the same time the dataset was created.
2485 Any editable ZFS property can also be set at creation time.
2486 Multiple
2487 .Fl o
2488 options can be specified.
2489 An error results if the same property is specified in multiple
2490 .Fl o
2491 options.
2492 .It Fl p
2493 Creates all the non-existing parent datasets.
2494 Datasets created in this manner are automatically mounted according to the
2495 .Sy mountpoint
2496 property inherited from their parent.
2497 Any property specified on the command line using the
2498 .Fl o
2499 option is ignored.
2500 If the target filesystem already exists, the operation completes successfully.
2501 .El
2502 .It Xo
2503 .Nm
2504 .Cm create
2505 .Op Fl ps
2506 .Op Fl b Ar blocksize
2507 .Oo Fl o Ar property Ns = Ns Ar value Oc Ns ...
2508 .Fl V Ar size Ar volume
2509 .Xc
2510 Creates a volume of the given size.
2511 The volume is exported as a block device in
2512 .Pa /dev/zvol/path ,
2513 where
2514 .Em path
2515 is the name of the volume in the ZFS namespace.
2516 The size represents the logical size as exported by the device.
2517 By default, a reservation of equal size is created.
2518 .Pp
2519 .Ar size
2520 is automatically rounded up to the nearest 128 Kbytes to ensure that the volume
2521 has an integral number of blocks regardless of
2522 .Sy blocksize .
2523 .Bl -tag -width "-b"
2524 .It Fl b Ar blocksize
2525 Equivalent to
2526 .Fl o Sy volblocksize Ns = Ns Ar blocksize .
2527 If this option is specified in conjunction with
2528 .Fl o Sy volblocksize ,
2529 the resulting behavior is undefined.
2530 .It Fl o Ar property Ns = Ns Ar value
2531 Sets the specified property as if the
2532 .Nm zfs Cm set Ar property Ns = Ns Ar value
2533 command was invoked at the same time the dataset was created.
2534 Any editable ZFS property can also be set at creation time.
2535 Multiple
2536 .Fl o
2537 options can be specified.
2538 An error results if the same property is specified in multiple
2539 .Fl o
2540 options.
2541 .It Fl p
2542 Creates all the non-existing parent datasets.
2543 Datasets created in this manner are automatically mounted according to the
2544 .Sy mountpoint
2545 property inherited from their parent.
2546 Any property specified on the command line using the
2547 .Fl o
2548 option is ignored.
2549 If the target filesystem already exists, the operation completes successfully.
2550 .It Fl s
2551 Creates a sparse volume with no reservation.
2552 See
2553 .Sy volsize
2554 in the
2555 .Sx Native Properties
2556 section for more information about sparse volumes.
2557 .El
2558 .It Xo
2559 .Nm
2560 .Cm destroy
2561 .Op Fl Rfnprv
2562 .Ar filesystem Ns | Ns Ar volume
2563 .Xc
2564 Destroys the given dataset.
2565 By default, the command unshares any file systems that are currently shared,
2566 unmounts any file systems that are currently mounted, and refuses to destroy a
2567 dataset that has active dependents
2568 .Pq children or clones .
2569 .Bl -tag -width "-R"
2570 .It Fl R
2571 Recursively destroy all dependents, including cloned file systems outside the
2572 target hierarchy.
2573 .It Fl f
2574 Force an unmount of any file systems using the
2575 .Nm unmount Fl f
2576 command.
2577 This option has no effect on non-file systems or unmounted file systems.
2578 .It Fl n
2579 Do a dry-run
2580 .Pq Qq No-op
2581 deletion.
2582 No data will be deleted.
2583 This is useful in conjunction with the
2584 .Fl v
2585 or
2586 .Fl p
2587 flags to determine what data would be deleted.
2588 .It Fl p
2589 Print machine-parsable verbose information about the deleted data.
2590 .It Fl r
2591 Recursively destroy all children.
2592 .It Fl v
2593 Print verbose information about the deleted data.
2594 .El
2595 .Pp
2596 Extreme care should be taken when applying either the
2597 .Fl r
2598 or the
2599 .Fl R
2600 options, as they can destroy large portions of a pool and cause unexpected
2601 behavior for mounted file systems in use.
2602 .It Xo
2603 .Nm
2604 .Cm destroy
2605 .Op Fl Rdnprv
2606 .Ar filesystem Ns | Ns Ar volume Ns @ Ns Ar snap Ns
2607 .Oo % Ns Ar snap Ns Oo , Ns Ar snap Ns Oo % Ns Ar snap Oc Oc Oc Ns ...
2608 .Xc
2609 The given snapshots are destroyed immediately if and only if the
2610 .Nm zfs Cm destroy
2611 command without the
2612 .Fl d
2613 option would have destroyed it.
2614 Such immediate destruction would occur, for example, if the snapshot had no
2615 clones and the user-initiated reference count were zero.
2616 .Pp
2617 If a snapshot does not qualify for immediate destruction, it is marked for
2618 deferred deletion.
2619 In this state, it exists as a usable, visible snapshot until both of the
2620 preconditions listed above are met, at which point it is destroyed.
2621 .Pp
2622 An inclusive range of snapshots may be specified by separating the first and
2623 last snapshots with a percent sign.
2624 The first and/or last snapshots may be left blank, in which case the
2625 filesystem's oldest or newest snapshot will be implied.
2626 .Pp
2627 Multiple snapshots
2628 .Pq or ranges of snapshots
2629 of the same filesystem or volume may be specified in a comma-separated list of
2630 snapshots.
2631 Only the snapshot's short name
2632 .Po the part after the
2633 .Sy @
2634 .Pc
2635 should be specified when using a range or comma-separated list to identify
2636 multiple snapshots.
2637 .Bl -tag -width "-R"
2638 .It Fl R
2639 Recursively destroy all clones of these snapshots, including the clones,
2640 snapshots, and children.
2641 If this flag is specified, the
2642 .Fl d
2643 flag will have no effect.
2644 .It Fl d
2645 Destroy immediately. If a snapshot cannot be destroyed now, mark it for
2646 deferred destruction.
2647 .It Fl n
2648 Do a dry-run
2649 .Pq Qq No-op
2650 deletion.
2651 No data will be deleted.
2652 This is useful in conjunction with the
2653 .Fl p
2654 or
2655 .Fl v
2656 flags to determine what data would be deleted.
2657 .It Fl p
2658 Print machine-parsable verbose information about the deleted data.
2659 .It Fl r
2660 Destroy
2661 .Pq or mark for deferred deletion
2662 all snapshots with this name in descendent file systems.
2663 .It Fl v
2664 Print verbose information about the deleted data.
2665 .Pp
2666 Extreme care should be taken when applying either the
2667 .Fl r
2668 or the
2669 .Fl R
2670 options, as they can destroy large portions of a pool and cause unexpected
2671 behavior for mounted file systems in use.
2672 .El
2673 .It Xo
2674 .Nm
2675 .Cm destroy
2676 .Ar filesystem Ns | Ns Ar volume Ns # Ns Ar bookmark
2677 .Xc
2678 The given bookmark is destroyed.
2679 .It Xo
2680 .Nm
2681 .Cm snapshot
2682 .Op Fl r
2683 .Oo Fl o Ar property Ns = Ns Ar value Oc Ns ...
2684 .Ar filesystem Ns @ Ns Ar snapname Ns | Ns Ar volume Ns @ Ns Ar snapname Ns ...
2685 .Xc
2686 Creates snapshots with the given names.
2687 All previous modifications by successful system calls to the file system are
2688 part of the snapshots.
2689 Snapshots are taken atomically, so that all snapshots correspond to the same
2690 moment in time.
2691 .Nm zfs Cm snap
2692 can be used as an alias for
2693 .Nm zfs Cm snapshot.
2694 See the
2695 .Sx Snapshots
2696 section for details.
2697 .Bl -tag -width "-o"
2698 .It Fl o Ar property Ns = Ns Ar value
2699 Sets the specified property; see
2700 .Nm zfs Cm create
2701 for details.
2702 .It Fl r
2703 Recursively create snapshots of all descendent datasets
2704 .El
2705 .It Xo
2706 .Nm
2707 .Cm rollback
2708 .Op Fl Rfr
2709 .Ar snapshot
2710 .Xc
2711 Roll back the given dataset to a previous snapshot.
2712 When a dataset is rolled back, all data that has changed since the snapshot is
2713 discarded, and the dataset reverts to the state at the time of the snapshot.
2714 By default, the command refuses to roll back to a snapshot other than the most
2715 recent one.
2716 In order to do so, all intermediate snapshots and bookmarks must be destroyed by
2717 specifying the
2718 .Fl r
2719 option.
2720 .Pp
2721 The
2722 .Fl rR
2723 options do not recursively destroy the child snapshots of a recursive snapshot.
2724 Only direct snapshots of the specified filesystem are destroyed by either of
2725 these options.
2726 To completely roll back a recursive snapshot, you must rollback the individual
2727 child snapshots.
2728 .Bl -tag -width "-R"
2729 .It Fl R
2730 Destroy any more recent snapshots and bookmarks, as well as any clones of those
2731 snapshots.
2732 .It Fl f
2733 Used with the
2734 .Fl R
2735 option to force an unmount of any clone file systems that are to be destroyed.
2736 .It Fl r
2737 Destroy any snapshots and bookmarks more recent than the one specified.
2738 .El
2739 .It Xo
2740 .Nm
2741 .Cm clone
2742 .Op Fl p
2743 .Oo Fl o Ar property Ns = Ns Ar value Oc Ns ...
2744 .Ar snapshot Ar filesystem Ns | Ns Ar volume
2745 .Xc
2746 Creates a clone of the given snapshot.
2747 See the
2748 .Sx Clones
2749 section for details.
2750 The target dataset can be located anywhere in the ZFS hierarchy, and is created
2751 as the same type as the original.
2752 .Bl -tag -width "-o"
2753 .It Fl o Ar property Ns = Ns Ar value
2754 Sets the specified property; see
2755 .Nm zfs Cm create
2756 for details.
2757 .It Fl p
2758 Creates all the non-existing parent datasets.
2759 Datasets created in this manner are automatically mounted according to the
2760 .Sy mountpoint
2761 property inherited from their parent.
2762 If the target filesystem or volume already exists, the operation completes
2763 successfully.
2764 .El
2765 .It Xo
2766 .Nm
2767 .Cm promote
2768 .Ar clone-filesystem
2769 .Xc
2770 Promotes a clone file system to no longer be dependent on its
2771 .Qq origin
2772 snapshot.
2773 This makes it possible to destroy the file system that the clone was created
2774 from.
2775 The clone parent-child dependency relationship is reversed, so that the origin
2776 file system becomes a clone of the specified file system.
2777 .Pp
2778 The snapshot that was cloned, and any snapshots previous to this snapshot, are
2779 now owned by the promoted clone.
2780 The space they use moves from the origin file system to the promoted clone, so
2781 enough space must be available to accommodate these snapshots.
2782 No new space is consumed by this operation, but the space accounting is
2783 adjusted.
2784 The promoted clone must not have any conflicting snapshot names of its own.
2785 The
2786 .Cm rename
2787 subcommand can be used to rename any conflicting snapshots.
2788 .It Xo
2789 .Nm
2790 .Cm rename
2791 .Op Fl f
2792 .Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot
2793 .Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot
2794 .Xc
2795 .It Xo
2796 .Nm
2797 .Cm rename
2798 .Op Fl fp
2799 .Ar filesystem Ns | Ns Ar volume
2800 .Ar filesystem Ns | Ns Ar volume
2801 .Xc
2802 Renames the given dataset.
2803 The new target can be located anywhere in the ZFS hierarchy, with the exception
2804 of snapshots.
2805 Snapshots can only be renamed within the parent file system or volume.
2806 When renaming a snapshot, the parent file system of the snapshot does not need
2807 to be specified as part of the second argument.
2808 Renamed file systems can inherit new mount points, in which case they are
2809 unmounted and remounted at the new mount point.
2810 .Bl -tag -width "-a"
2811 .It Fl f
2812 Force unmount any filesystems that need to be unmounted in the process.
2813 .It Fl p
2814 Creates all the nonexistent parent datasets.
2815 Datasets created in this manner are automatically mounted according to the
2816 .Sy mountpoint
2817 property inherited from their parent.
2818 .El
2819 .It Xo
2820 .Nm
2821 .Cm rename
2822 .Fl r
2823 .Ar snapshot Ar snapshot
2824 .Xc
2825 Recursively rename the snapshots of all descendent datasets.
2826 Snapshots are the only dataset that can be renamed recursively.
2827 .It Xo
2828 .Nm
2829 .Cm list
2830 .Op Fl r Ns | Ns Fl d Ar depth
2831 .Op Fl Hp
2832 .Oo Fl o Ar property Ns Oo , Ns Ar property Oc Ns ... Oc
2833 .Oo Fl s Ar property Oc Ns ...
2834 .Oo Fl S Ar property Oc Ns ...
2835 .Oo Fl t Ar type Ns Oo , Ns Ar type Oc Ns ... Oc
2836 .Oo Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot Oc Ns ...
2837 .Xc
2838 Lists the property information for the given datasets in tabular form.
2839 If specified, you can list property information by the absolute pathname or the
2840 relative pathname.
2841 By default, all file systems and volumes are displayed.
2842 Snapshots are displayed if the
2843 .Sy listsnaps
2844 property is
2845 .Sy on
2846 .Po the default is
2847 .Sy off
2848 .Pc .
2849 The following fields are displayed:
2850 .Sy name Ns \&, Sy used Ns \&, Sy available Ns \&, Sy referenced Ns \&, Sy mountpoint Ns .
2851 .Bl -tag -width "-H"
2852 .It Fl H
2853 Used for scripting mode.
2854 Do not print headers and separate fields by a single tab instead of arbitrary
2855 white space.
2856 .It Fl S Ar property
2857 Same as the
2858 .Fl s
2859 option, but sorts by property in descending order.
2860 .It Fl d Ar depth
2861 Recursively display any children of the dataset, limiting the recursion to
2862 .Ar depth .
2863 A
2864 .Ar depth
2865 of
2866 .Sy 1
2867 will display only the dataset and its direct children.
2868 .It Fl o Ar property
2869 A comma-separated list of properties to display.
2870 The property must be:
2871 .Bl -bullet
2872 .It
2873 One of the properties described in the
2874 .Sx Native Properties
2875 section
2876 .It
2877 A user property
2878 .It
2879 The value
2880 .Sy name
2881 to display the dataset name
2882 .It
2883 The value
2884 .Sy space
2885 to display space usage properties on file systems and volumes.
2886 This is a shortcut for specifying
2887 .Fl o Sy name Ns \&, Ns Sy avail Ns \&, Ns Sy used Ns \&, Ns Sy usedsnap Ns \&, Ns
2888 .Sy usedds Ns \&, Ns Sy usedrefreserv Ns \&, Ns Sy usedchild Fl t
2889 .Sy filesystem Ns \&, Ns Sy volume
2890 syntax.
2891 .El
2892 .It Fl p
2893 Display numbers in parsable
2894 .Pq exact
2895 values.
2896 .It Fl r
2897 Recursively display any children of the dataset on the command line.
2898 .It Fl s Ar property
2899 A property for sorting the output by column in ascending order based on the
2900 value of the property.
2901 The property must be one of the properties described in the
2902 .Sx Properties
2903 section or the value
2904 .Sy name
2905 to sort by the dataset name.
2906 Multiple properties can be specified at one time using multiple
2907 .Fl s
2908 property options.
2909 Multiple
2910 .Fl s
2911 options are evaluated from left to right in decreasing order of importance.
2912 The following is a list of sorting criteria:
2913 .Bl -bullet
2914 .It
2915 Numeric types sort in numeric order.
2916 .It
2917 String types sort in alphabetical order.
2918 .It
2919 Types inappropriate for a row sort that row to the literal bottom, regardless of
2920 the specified ordering.
2921 .El
2922 .Pp
2923 If no sorting options are specified the existing behavior of
2924 .Nm zfs Cm list
2925 is preserved.
2926 .It Fl t Ar type
2927 A comma-separated list of types to display, where
2928 .Ar type
2929 is one of
2930 .Sy filesystem ,
2931 .Sy snapshot ,
2932 .Sy volume ,
2933 .Sy bookmark ,
2934 or
2935 .Sy all .
2936 For example, specifying
2937 .Fl t Sy snapshot
2938 displays only snapshots.
2939 .El
2940 .It Xo
2941 .Nm
2942 .Cm set
2943 .Ar property Ns = Ns Ar value Oo Ar property Ns = Ns Ar value Oc Ns ...
2944 .Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot Ns ...
2945 .Xc
2946 Sets the property or list of properties to the given value(s) for each dataset.
2947 Only some properties can be edited.
2948 See the
2949 .Sx Properties
2950 section for more information on what properties can be set and acceptable
2951 values.
2952 Numeric values can be specified as exact values, or in a human-readable form
2953 with a suffix of
2954 .Sy B , K , M , G , T , P , E , Z
2955 .Po for bytes, kilobytes, megabytes, gigabytes, terabytes, petabytes, exabytes,
2956 or zettabytes, respectively
2957 .Pc .
2958 User properties can be set on snapshots.
2959 For more information, see the
2960 .Sx User Properties
2961 section.
2962 .It Xo
2963 .Nm
2964 .Cm get
2965 .Op Fl r Ns | Ns Fl d Ar depth
2966 .Op Fl Hp
2967 .Oo Fl o Ar field Ns Oo , Ns Ar field Oc Ns ... Oc
2968 .Oo Fl s Ar source Ns Oo , Ns Ar source Oc Ns ... Oc
2969 .Oo Fl t Ar type Ns Oo , Ns Ar type Oc Ns ... Oc
2970 .Cm all | Ar property Ns Oo , Ns Ar property Oc Ns ...
2971 .Oo Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot Ns | Ns Ar bookmark Oc Ns ...
2972 .Xc
2973 Displays properties for the given datasets.
2974 If no datasets are specified, then the command displays properties for all
2975 datasets on the system.
2976 For each property, the following columns are displayed:
2977 .Bd -literal
2978 name Dataset name
2979 property Property name
2980 value Property value
2981 source Property source \fBlocal\fP, \fBdefault\fP, \fBinherited\fP,
2982 \fBtemporary\fP, \fBreceived\fP or none (\fB-\fP).
2983 .Ed
2984 .Pp
2985 All columns are displayed by default, though this can be controlled by using the
2986 .Fl o
2987 option.
2988 This command takes a comma-separated list of properties as described in the
2989 .Sx Native Properties
2990 and
2991 .Sx User Properties
2992 sections.
2993 .Pp
2994 The value
2995 .Sy all
2996 can be used to display all properties that apply to the given dataset's type
2997 .Pq filesystem, volume, snapshot, or bookmark .
2998 .Bl -tag -width "-H"
2999 .It Fl H
3000 Display output in a form more easily parsed by scripts.
3001 Any headers are omitted, and fields are explicitly separated by a single tab
3002 instead of an arbitrary amount of space.
3003 .It Fl d Ar depth
3004 Recursively display any children of the dataset, limiting the recursion to
3005 .Ar depth .
3006 A depth of
3007 .Sy 1
3008 will display only the dataset and its direct children.
3009 .It Fl o Ar field
3010 A comma-separated list of columns to display.
3011 .Sy name Ns \&, Ns Sy property Ns \&, Ns Sy value Ns \&, Ns Sy source
3012 is the default value.
3013 .It Fl p
3014 Display numbers in parsable
3015 .Pq exact
3016 values.
3017 .It Fl r
3018 Recursively display properties for any children.
3019 .It Fl s Ar source
3020 A comma-separated list of sources to display.
3021 Those properties coming from a source other than those in this list are ignored.
3022 Each source must be one of the following:
3023 .Sy local ,
3024 .Sy default ,
3025 .Sy inherited ,
3026 .Sy temporary ,
3027 .Sy received ,
3028 and
3029 .Sy none .
3030 The default value is all sources.
3031 .It Fl t Ar type
3032 A comma-separated list of types to display, where
3033 .Ar type
3034 is one of
3035 .Sy filesystem ,
3036 .Sy snapshot ,
3037 .Sy volume ,
3038 .Sy bookmark ,
3039 or
3040 .Sy all .
3041 .El
3042 .It Xo
3043 .Nm
3044 .Cm inherit
3045 .Op Fl rS
3046 .Ar property Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot Ns ...
3047 .Xc
3048 Clears the specified property, causing it to be inherited from an ancestor,
3049 restored to default if no ancestor has the property set, or with the
3050 .Fl S
3051 option reverted to the received value if one exists.
3052 See the
3053 .Sx Properties
3054 section for a listing of default values, and details on which properties can be
3055 inherited.
3056 .Bl -tag -width "-r"
3057 .It Fl r
3058 Recursively inherit the given property for all children.
3059 .It Fl S
3060 Revert the property to the received value if one exists; otherwise operate as
3061 if the
3062 .Fl S
3063 option was not specified.
3064 .El
3065 .It Xo
3066 .Nm
3067 .Cm upgrade
3068 .Xc
3069 Displays a list of file systems that are not the most recent version.
3070 .It Xo
3071 .Nm
3072 .Cm upgrade
3073 .Fl v
3074 .Xc
3075 Displays a list of currently supported file system versions.
3076 .It Xo
3077 .Nm
3078 .Cm upgrade
3079 .Op Fl r
3080 .Op Fl V Ar version
3081 .Fl a | Ar filesystem
3082 .Xc
3083 Upgrades file systems to a new on-disk version.
3084 Once this is done, the file systems will no longer be accessible on systems
3085 running older versions of the software.
3086 .Nm zfs Cm send
3087 streams generated from new snapshots of these file systems cannot be accessed on
3088 systems running older versions of the software.
3089 .Pp
3090 In general, the file system version is independent of the pool version.
3091 See
3092 .Xr zpool 8
3093 for information on the
3094 .Nm zpool Cm upgrade
3095 command.
3096 .Pp
3097 In some cases, the file system version and the pool version are interrelated and
3098 the pool version must be upgraded before the file system version can be
3099 upgraded.
3100 .Bl -tag -width "-V"
3101 .It Fl V Ar version
3102 Upgrade to the specified
3103 .Ar version .
3104 If the
3105 .Fl V
3106 flag is not specified, this command upgrades to the most recent version.
3107 This
3108 option can only be used to increase the version number, and only up to the most
3109 recent version supported by this software.
3110 .It Fl a
3111 Upgrade all file systems on all imported pools.
3112 .It Ar filesystem
3113 Upgrade the specified file system.
3114 .It Fl r
3115 Upgrade the specified file system and all descendent file systems.
3116 .El
3117 .It Xo
3118 .Nm
3119 .Cm userspace
3120 .Op Fl Hinp
3121 .Oo Fl o Ar field Ns Oo , Ns Ar field Oc Ns ... Oc
3122 .Oo Fl s Ar field Oc Ns ...
3123 .Oo Fl S Ar field Oc Ns ...
3124 .Oo Fl t Ar type Ns Oo , Ns Ar type Oc Ns ... Oc
3125 .Ar filesystem Ns | Ns Ar snapshot
3126 .Xc
3127 Displays space consumed by, and quotas on, each user in the specified filesystem
3128 or snapshot.
3129 This corresponds to the
3130 .Sy userused@ Ns Em user ,
3131 .Sy userobjused@ Ns Em user ,
3132 .Sy userquota@ Ns Em user,
3133 and
3134 .Sy userobjquota@ Ns Em user
3135 properties.
3136 .Bl -tag -width "-H"
3137 .It Fl H
3138 Do not print headers, use tab-delimited output.
3139 .It Fl S Ar field
3140 Sort by this field in reverse order.
3141 See
3142 .Fl s .
3143 .It Fl i
3144 Translate SID to POSIX ID.
3145 The POSIX ID may be ephemeral if no mapping exists.
3146 Normal POSIX interfaces
3147 .Po for example,
3148 .Xr stat 2 ,
3149 .Nm ls Fl l
3150 .Pc
3151 perform this translation, so the
3152 .Fl i
3153 option allows the output from
3154 .Nm zfs Cm userspace
3155 to be compared directly with those utilities.
3156 However,
3157 .Fl i
3158 may lead to confusion if some files were created by an SMB user before a
3159 SMB-to-POSIX name mapping was established.
3160 In such a case, some files will be owned by the SMB entity and some by the POSIX
3161 entity.
3162 However, the
3163 .Fl i
3164 option will report that the POSIX entity has the total usage and quota for both.
3165 .It Fl n
3166 Print numeric ID instead of user/group name.
3167 .It Fl o Ar field Ns Oo , Ns Ar field Oc Ns ...
3168 Display only the specified fields from the following set:
3169 .Sy type ,
3170 .Sy name ,
3171 .Sy used ,
3172 .Sy quota .
3173 The default is to display all fields.
3174 .It Fl p
3175 Use exact
3176 .Pq parsable
3177 numeric output.
3178 .It Fl s Ar field
3179 Sort output by this field.
3180 The
3181 .Fl s
3182 and
3183 .Fl S
3184 flags may be specified multiple times to sort first by one field, then by
3185 another.
3186 The default is
3187 .Fl s Sy type Fl s Sy name .
3188 .It Fl t Ar type Ns Oo , Ns Ar type Oc Ns ...
3189 Print only the specified types from the following set:
3190 .Sy all ,
3191 .Sy posixuser ,
3192 .Sy smbuser ,
3193 .Sy posixgroup ,
3194 .Sy smbgroup .
3195 The default is
3196 .Fl t Sy posixuser Ns \&, Ns Sy smbuser .
3197 The default can be changed to include group types.
3198 .El
3199 .It Xo
3200 .Nm
3201 .Cm groupspace
3202 .Op Fl Hinp
3203 .Oo Fl o Ar field Ns Oo , Ns Ar field Oc Ns ... Oc
3204 .Oo Fl s Ar field Oc Ns ...
3205 .Oo Fl S Ar field Oc Ns ...
3206 .Oo Fl t Ar type Ns Oo , Ns Ar type Oc Ns ... Oc
3207 .Ar filesystem Ns | Ns Ar snapshot
3208 .Xc
3209 Displays space consumed by, and quotas on, each group in the specified
3210 filesystem or snapshot.
3211 This subcommand is identical to
3212 .Nm zfs Cm userspace ,
3213 except that the default types to display are
3214 .Fl t Sy posixgroup Ns \&, Ns Sy smbgroup .
3215 .It Xo
3216 .Nm
3217 .Cm projectspace
3218 .Op Fl Hp
3219 .Oo Fl o Ar field Ns Oo , Ns Ar field Oc Ns ... Oc
3220 .Oo Fl s Ar field Oc Ns ...
3221 .Oo Fl S Ar field Oc Ns ...
3222 .Ar filesystem Ns | Ns Ar snapshot
3223 .Xc
3224 Displays space consumed by, and quotas on, each project in the specified
3225 filesystem or snapshot. This subcommand is identical to
3226 .Nm zfs Cm userspace ,
3227 except that the project identifier is numeral, not name. So need neither
3228 the option
3229 .Sy -i
3230 for SID to POSIX ID nor
3231 .Sy -n
3232 for numeric ID, nor
3233 .Sy -t
3234 for types.
3235 .It Xo
3236 .Nm
3237 .Cm project
3238 .Oo Fl d Ns | Ns Fl r Ns Oc
3239 .Ar file Ns | Ns Ar directory Ns ...
3240 .Xc
3241 List project identifier (ID) and inherit flag of file(s) or directories.
3242 .Bl -tag -width "-d"
3243 .It Fl d
3244 Show the directory project ID and inherit flag, not its childrens. It will
3245 overwrite the former specified
3246 .Fl r
3247 option.
3248 .It Fl r
3249 Show on subdirectories recursively. It will overwrite the former specified
3250 .Fl d
3251 option.
3252 .El
3253 .It Xo
3254 .Nm
3255 .Cm project
3256 .Fl C
3257 .Oo Fl kr Ns Oc
3258 .Ar file Ns | Ns Ar directory Ns ...
3259 .Xc
3260 Clear project inherit flag and/or ID on the file(s) or directories.
3261 .Bl -tag -width "-k"
3262 .It Fl k
3263 Keep the project ID unchanged. If not specified, the project ID will be reset
3264 as zero.
3265 .It Fl r
3266 Clear on subdirectories recursively.
3267 .El
3268 .It Xo
3269 .Nm
3270 .Cm project
3271 .Fl c
3272 .Oo Fl 0 Ns Oc
3273 .Oo Fl d Ns | Ns Fl r Ns Oc
3274 .Op Fl p Ar id
3275 .Ar file Ns | Ns Ar directory Ns ...
3276 .Xc
3277 Check project ID and inherit flag on the file(s) or directories, report the
3278 entries without project inherit flag or with different project IDs from the
3279 specified (via
3280 .Fl p
3281 option) value or the target directory's project ID.
3282 .Bl -tag -width "-0"
3283 .It Fl 0
3284 Print file name with a trailing NUL instead of newline (by default), like
3285 "find -print0".
3286 .It Fl d
3287 Check the directory project ID and inherit flag, not its childrens. It will
3288 overwrite the former specified
3289 .Fl r
3290 option.
3291 .It Fl p
3292 Specify the referenced ID for comparing with the target file(s) or directories'
3293 project IDs. If not specified, the target (top) directory's project ID will be
3294 used as the referenced one.
3295 .It Fl r
3296 Check on subdirectories recursively. It will overwrite the former specified
3297 .Fl d
3298 option.
3299 .El
3300 .It Xo
3301 .Nm
3302 .Cm project
3303 .Op Fl p Ar id
3304 .Oo Fl rs Ns Oc
3305 .Ar file Ns | Ns Ar directory Ns ...
3306 .Xc
3307 .Bl -tag -width "-p"
3308 Set project ID and/or inherit flag on the file(s) or directories.
3309 .It Fl p
3310 Set the file(s)' or directories' project ID with the given value.
3311 .It Fl r
3312 Set on subdirectories recursively.
3313 .It Fl s
3314 Set project inherit flag on the given file(s) or directories. It is usually used
3315 for setup tree quota on the directory target with
3316 .Fl r
3317 option specified together. When setup tree quota, by default the directory's
3318 project ID will be set to all its descendants unless you specify the project
3319 ID via
3320 .Fl p
3321 option explicitly.
3322 .El
3323 .It Xo
3324 .Nm
3325 .Cm mount
3326 .Xc
3327 Displays all ZFS file systems currently mounted.
3328 .It Xo
3329 .Nm
3330 .Cm mount
3331 .Op Fl Olv
3332 .Op Fl o Ar options
3333 .Fl a | Ar filesystem
3334 .Xc
3335 Mount ZFS filesystem on a path described by its
3336 .Sy mountpoint
3337 property, if the path exists and is empty. If
3338 .Sy mountpoint
3339 is set to
3340 .Em legacy ,
3341 the filesystem should be instead mounted using
3342 .Xr mount 8 .
3343 .Bl -tag -width "-O"
3344 .It Fl O
3345 Perform an overlay mount. Allows mounting in non-empty
3346 .Sy mountpoint .
3347 See
3348 .Xr mount 8
3349 for more information.
3350 .It Fl a
3351 Mount all available ZFS file systems.
3352 Invoked automatically as part of the boot process if configured.
3353 .It Ar filesystem
3354 Mount the specified filesystem.
3355 .It Fl o Ar options
3356 An optional, comma-separated list of mount options to use temporarily for the
3357 duration of the mount.
3358 See the
3359 .Sx Temporary Mount Point Properties
3360 section for details.
3361 .It Fl l
3362 Load keys for encrypted filesystems as they are being mounted. This is
3363 equivalent to executing
3364 .Nm zfs Cm load-key
3365 on each encryption root before mounting it. Note that if a filesystem has a
3366 .Sy keylocation
3367 of
3368 .Sy prompt
3369 this will cause the terminal to interactively block after asking for the key.
3370 .It Fl v
3371 Report mount progress.
3372 .El
3373 .It Xo
3374 .Nm
3375 .Cm unmount
3376 .Op Fl f
3377 .Fl a | Ar filesystem Ns | Ns Ar mountpoint
3378 .Xc
3379 Unmounts currently mounted ZFS file systems.
3380 .Bl -tag -width "-a"
3381 .It Fl a
3382 Unmount all available ZFS file systems.
3383 Invoked automatically as part of the shutdown process.
3384 .It Ar filesystem Ns | Ns Ar mountpoint
3385 Unmount the specified filesystem.
3386 The command can also be given a path to a ZFS file system mount point on the
3387 system.
3388 .It Fl f
3389 Forcefully unmount the file system, even if it is currently in use.
3390 .El
3391 .It Xo
3392 .Nm
3393 .Cm share
3394 .Fl a | Ar filesystem
3395 .Xc
3396 Shares available ZFS file systems.
3397 .Bl -tag -width "-a"
3398 .It Fl a
3399 Share all available ZFS file systems.
3400 Invoked automatically as part of the boot process.
3401 .It Ar filesystem
3402 Share the specified filesystem according to the
3403 .Sy sharenfs
3404 and
3405 .Sy sharesmb
3406 properties.
3407 File systems are shared when the
3408 .Sy sharenfs
3409 or
3410 .Sy sharesmb
3411 property is set.
3412 .El
3413 .It Xo
3414 .Nm
3415 .Cm unshare
3416 .Fl a | Ar filesystem Ns | Ns Ar mountpoint
3417 .Xc
3418 Unshares currently shared ZFS file systems.
3419 .Bl -tag -width "-a"
3420 .It Fl a
3421 Unshare all available ZFS file systems.
3422 Invoked automatically as part of the shutdown process.
3423 .It Ar filesystem Ns | Ns Ar mountpoint
3424 Unshare the specified filesystem.
3425 The command can also be given a path to a ZFS file system shared on the system.
3426 .El
3427 .It Xo
3428 .Nm
3429 .Cm bookmark
3430 .Ar snapshot bookmark
3431 .Xc
3432 Creates a bookmark of the given snapshot.
3433 Bookmarks mark the point in time when the snapshot was created, and can be used
3434 as the incremental source for a
3435 .Nm zfs Cm send
3436 command.
3437 .Pp
3438 This feature must be enabled to be used.
3439 See
3440 .Xr zpool-features 5
3441 for details on ZFS feature flags and the
3442 .Sy bookmarks
3443 feature.
3444 .It Xo
3445 .Nm
3446 .Cm send
3447 .Op Fl DLPRbcehnpvw
3448 .Op Oo Fl I Ns | Ns Fl i Oc Ar snapshot
3449 .Ar snapshot
3450 .Xc
3451 Creates a stream representation of the second
3452 .Ar snapshot ,
3453 which is written to standard output.
3454 The output can be redirected to a file or to a different system
3455 .Po for example, using
3456 .Xr ssh 1
3457 .Pc .
3458 By default, a full stream is generated.
3459 .Bl -tag -width "-D"
3460 .It Fl D, -dedup
3461 Generate a deduplicated stream.
3462 Blocks which would have been sent multiple times in the send stream will only be
3463 sent once.
3464 The receiving system must also support this feature to receive a deduplicated
3465 stream.
3466 This flag can be used regardless of the dataset's
3467 .Sy dedup
3468 property, but performance will be much better if the filesystem uses a
3469 dedup-capable checksum
3470 .Po for example,
3471 .Sy sha256
3472 .Pc .
3473 .It Fl I Ar snapshot
3474 Generate a stream package that sends all intermediary snapshots from the first
3475 snapshot to the second snapshot.
3476 For example,
3477 .Fl I Em @a Em fs@d
3478 is similar to
3479 .Fl i Em @a Em fs@b Ns \&; Fl i Em @b Em fs@c Ns \&; Fl i Em @c Em fs@d .
3480 The incremental source may be specified as with the
3481 .Fl i
3482 option.
3483 .It Fl L, -large-block
3484 Generate a stream which may contain blocks larger than 128KB.
3485 This flag has no effect if the
3486 .Sy large_blocks
3487 pool feature is disabled, or if the
3488 .Sy recordsize
3489 property of this filesystem has never been set above 128KB.
3490 The receiving system must have the
3491 .Sy large_blocks
3492 pool feature enabled as well.
3493 See
3494 .Xr zpool-features 5
3495 for details on ZFS feature flags and the
3496 .Sy large_blocks
3497 feature.
3498 .It Fl P, -parsable
3499 Print machine-parsable verbose information about the stream package generated.
3500 .It Fl R, -replicate
3501 Generate a replication stream package, which will replicate the specified
3502 file system, and all descendent file systems, up to the named snapshot.
3503 When received, all properties, snapshots, descendent file systems, and clones
3504 are preserved.
3505 .Pp
3506 If the
3507 .Fl i
3508 or
3509 .Fl I
3510 flags are used in conjunction with the
3511 .Fl R
3512 flag, an incremental replication stream is generated.
3513 The current values of properties, and current snapshot and file system names are
3514 set when the stream is received.
3515 If the
3516 .Fl F
3517 flag is specified when this stream is received, snapshots and file systems that
3518 do not exist on the sending side are destroyed. If the
3519 .Fl R
3520 flag is used to send encrypted datasets, then
3521 .Fl w
3522 must also be specified.
3523 .It Fl e, -embed
3524 Generate a more compact stream by using
3525 .Sy WRITE_EMBEDDED
3526 records for blocks which are stored more compactly on disk by the
3527 .Sy embedded_data
3528 pool feature.
3529 This flag has no effect if the
3530 .Sy embedded_data
3531 feature is disabled.
3532 The receiving system must have the
3533 .Sy embedded_data
3534 feature enabled.
3535 If the
3536 .Sy lz4_compress
3537 feature is active on the sending system, then the receiving system must have
3538 that feature enabled as well. Datasets that are sent with this flag may not be
3539 received as an encrypted dataset, since encrypted datasets cannot use the
3540 .Sy embedded_data
3541 feature.
3542 See
3543 .Xr zpool-features 5
3544 for details on ZFS feature flags and the
3545 .Sy embedded_data
3546 feature.
3547 .It Fl b, -backup
3548 Sends only received property values whether or not they are overridden by local
3549 settings, but only if the dataset has ever been received. Use this option when
3550 you want
3551 .Nm zfs Cm receive
3552 to restore received properties backed up on the sent dataset and to avoid
3553 sending local settings that may have nothing to do with the source dataset,
3554 but only with how the data is backed up.
3555 .It Fl c, -compressed
3556 Generate a more compact stream by using compressed WRITE records for blocks
3557 which are compressed on disk and in memory
3558 .Po see the
3559 .Sy compression
3560 property for details
3561 .Pc .
3562 If the
3563 .Sy lz4_compress
3564 feature is active on the sending system, then the receiving system must have
3565 that feature enabled as well.
3566 If the
3567 .Sy large_blocks
3568 feature is enabled on the sending system but the
3569 .Fl L
3570 option is not supplied in conjunction with
3571 .Fl c ,
3572 then the data will be decompressed before sending so it can be split into
3573 smaller block sizes.
3574 .It Fl w, -raw
3575 For encrypted datasets, send data exactly as it exists on disk. This allows
3576 backups to be taken even if encryption keys are not currently loaded. The
3577 backup may then be received on an untrusted machine since that machine will
3578 not have the encryption keys to read the protected data or alter it without
3579 being detected. Upon being received, the dataset will have the same encryption
3580 keys as it did on the send side, although the
3581 .Sy keylocation
3582 property will be defaulted to
3583 .Sy prompt
3584 if not otherwise provided. For unencrypted datasets, this flag will be
3585 equivalent to
3586 .Fl Lec .
3587 Note that if you do not use this flag for sending encrypted datasets, data will
3588 be sent unencrypted and may be re-encrypted with a different encryption key on
3589 the receiving system, which will disable the ability to do a raw send to that
3590 system for incrementals.
3591 .It Fl h, -holds
3592 Generate a stream package that includes any snapshot holds (created with the
3593 .Sy zfs hold
3594 command), and indicating to
3595 .Sy zfs receive
3596 that the holds be applied to the dataset on the receiving system.
3597 .It Fl i Ar snapshot
3598 Generate an incremental stream from the first
3599 .Ar snapshot
3600 .Pq the incremental source
3601 to the second
3602 .Ar snapshot
3603 .Pq the incremental target .
3604 The incremental source can be specified as the last component of the snapshot
3605 name
3606 .Po the
3607 .Sy @
3608 character and following
3609 .Pc
3610 and it is assumed to be from the same file system as the incremental target.
3611 .Pp
3612 If the destination is a clone, the source may be the origin snapshot, which must
3613 be fully specified
3614 .Po for example,
3615 .Em pool/fs@origin ,
3616 not just
3617 .Em @origin
3618 .Pc .
3619 .It Fl n, -dryrun
3620 Do a dry-run
3621 .Pq Qq No-op
3622 send.
3623 Do not generate any actual send data.
3624 This is useful in conjunction with the
3625 .Fl v
3626 or
3627 .Fl P
3628 flags to determine what data will be sent.
3629 In this case, the verbose output will be written to standard output
3630 .Po contrast with a non-dry-run, where the stream is written to standard output
3631 and the verbose output goes to standard error
3632 .Pc .
3633 .It Fl p, -props
3634 Include the dataset's properties in the stream.
3635 This flag is implicit when
3636 .Fl R
3637 is specified.
3638 The receiving system must also support this feature. Sends of encrypted datasets
3639 must use
3640 .Fl w
3641 when using this flag.
3642 .It Fl v, -verbose
3643 Print verbose information about the stream package generated.
3644 This information includes a per-second report of how much data has been sent.
3645 .Pp
3646 The format of the stream is committed.
3647 You will be able to receive your streams on future versions of ZFS.
3648 .El
3649 .It Xo
3650 .Nm
3651 .Cm send
3652 .Op Fl LPcenvw
3653 .Op Fl i Ar snapshot Ns | Ns Ar bookmark
3654 .Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot
3655 .Xc
3656 Generate a send stream, which may be of a filesystem, and may be incremental
3657 from a bookmark.
3658 If the destination is a filesystem or volume, the pool must be read-only, or the
3659 filesystem must not be mounted.
3660 When the stream generated from a filesystem or volume is received, the default
3661 snapshot name will be
3662 .Qq --head-- .
3663 .Bl -tag -width "-L"
3664 .It Fl L, -large-block
3665 Generate a stream which may contain blocks larger than 128KB.
3666 This flag has no effect if the
3667 .Sy large_blocks
3668 pool feature is disabled, or if the
3669 .Sy recordsize
3670 property of this filesystem has never been set above 128KB.
3671 The receiving system must have the
3672 .Sy large_blocks
3673 pool feature enabled as well.
3674 See
3675 .Xr zpool-features 5
3676 for details on ZFS feature flags and the
3677 .Sy large_blocks
3678 feature.
3679 .It Fl P, -parsable
3680 Print machine-parsable verbose information about the stream package generated.
3681 .It Fl c, -compressed
3682 Generate a more compact stream by using compressed WRITE records for blocks
3683 which are compressed on disk and in memory
3684 .Po see the
3685 .Sy compression
3686 property for details
3687 .Pc .
3688 If the
3689 .Sy lz4_compress
3690 feature is active on the sending system, then the receiving system must have
3691 that feature enabled as well.
3692 If the
3693 .Sy large_blocks
3694 feature is enabled on the sending system but the
3695 .Fl L
3696 option is not supplied in conjunction with
3697 .Fl c ,
3698 then the data will be decompressed before sending so it can be split into
3699 smaller block sizes.
3700 .It Fl w, -raw
3701 For encrypted datasets, send data exactly as it exists on disk. This allows
3702 backups to be taken even if encryption keys are not currently loaded. The
3703 backup may then be received on an untrusted machine since that machine will
3704 not have the encryption keys to read the protected data or alter it without
3705 being detected. Upon being received, the dataset will have the same encryption
3706 keys as it did on the send side, although the
3707 .Sy keylocation
3708 property will be defaulted to
3709 .Sy prompt
3710 if not otherwise provided. For unencrypted datasets, this flag will be
3711 equivalent to
3712 .Fl Lec .
3713 Note that if you do not use this flag for sending encrypted datasets, data will
3714 be sent unencrypted and may be re-encrypted with a different encryption key on
3715 the receiving system, which will disable the ability to do a raw send to that
3716 system for incrementals.
3717 .It Fl e, -embed
3718 Generate a more compact stream by using
3719 .Sy WRITE_EMBEDDED
3720 records for blocks which are stored more compactly on disk by the
3721 .Sy embedded_data
3722 pool feature.
3723 This flag has no effect if the
3724 .Sy embedded_data
3725 feature is disabled.
3726 The receiving system must have the
3727 .Sy embedded_data
3728 feature enabled.
3729 If the
3730 .Sy lz4_compress
3731 feature is active on the sending system, then the receiving system must have
3732 that feature enabled as well. Datasets that are sent with this flag may not be
3733 received as an encrypted dataset, since encrypted datasets cannot use the
3734 .Sy embedded_data
3735 feature.
3736 See
3737 .Xr zpool-features 5
3738 for details on ZFS feature flags and the
3739 .Sy embedded_data
3740 feature.
3741 .It Fl i Ar snapshot Ns | Ns Ar bookmark
3742 Generate an incremental send stream.
3743 The incremental source must be an earlier snapshot in the destination's history.
3744 It will commonly be an earlier snapshot in the destination's file system, in
3745 which case it can be specified as the last component of the name
3746 .Po the
3747 .Sy #
3748 or
3749 .Sy @
3750 character and following
3751 .Pc .
3752 .Pp
3753 If the incremental target is a clone, the incremental source can be the origin
3754 snapshot, or an earlier snapshot in the origin's filesystem, or the origin's
3755 origin, etc.
3756 .It Fl n, -dryrun
3757 Do a dry-run
3758 .Pq Qq No-op
3759 send.
3760 Do not generate any actual send data.
3761 This is useful in conjunction with the
3762 .Fl v
3763 or
3764 .Fl P
3765 flags to determine what data will be sent.
3766 In this case, the verbose output will be written to standard output
3767 .Po contrast with a non-dry-run, where the stream is written to standard output
3768 and the verbose output goes to standard error
3769 .Pc .
3770 .It Fl v, -verbose
3771 Print verbose information about the stream package generated.
3772 This information includes a per-second report of how much data has been sent.
3773 .El
3774 .It Xo
3775 .Nm
3776 .Cm send
3777 .Op Fl Penv
3778 .Fl t
3779 .Ar receive_resume_token
3780 .Xc
3781 Creates a send stream which resumes an interrupted receive.
3782 The
3783 .Ar receive_resume_token
3784 is the value of this property on the filesystem or volume that was being
3785 received into.
3786 See the documentation for
3787 .Sy zfs receive -s
3788 for more details.
3789 .It Xo
3790 .Nm
3791 .Cm receive
3792 .Op Fl Fhnsuv
3793 .Op Fl o Sy origin Ns = Ns Ar snapshot
3794 .Op Fl o Ar property Ns = Ns Ar value
3795 .Op Fl x Ar property
3796 .Ar filesystem Ns | Ns Ar volume Ns | Ns Ar snapshot
3797 .Xc
3798 .It Xo
3799 .Nm
3800 .Cm receive
3801 .Op Fl Fhnsuv
3802 .Op Fl d Ns | Ns Fl e
3803 .Op Fl o Sy origin Ns = Ns Ar snapshot
3804 .Op Fl o Ar property Ns = Ns Ar value
3805 .Op Fl x Ar property
3806 .Ar filesystem
3807 .Xc
3808 Creates a snapshot whose contents are as specified in the stream provided on
3809 standard input.
3810 If a full stream is received, then a new file system is created as well.
3811 Streams are created using the
3812 .Nm zfs Cm send
3813 subcommand, which by default creates a full stream.
3814 .Nm zfs Cm recv
3815 can be used as an alias for
3816 .Nm zfs Cm receive.
3817 .Pp
3818 If an incremental stream is received, then the destination file system must
3819 already exist, and its most recent snapshot must match the incremental stream's
3820 source.
3821 For
3822 .Sy zvols ,
3823 the destination device link is destroyed and recreated, which means the
3824 .Sy zvol
3825 cannot be accessed during the
3826 .Cm receive
3827 operation.
3828 .Pp
3829 When a snapshot replication package stream that is generated by using the
3830 .Nm zfs Cm send Fl R
3831 command is received, any snapshots that do not exist on the sending location are
3832 destroyed by using the
3833 .Nm zfs Cm destroy Fl d
3834 command.
3835 .Pp
3836 If
3837 .Fl o Em property Ns = Ns Ar value
3838 or
3839 .Fl x Em property
3840 is specified, it applies to the effective value of the property throughout
3841 the entire subtree of replicated datasets. Effective property values will be
3842 set (
3843 .Fl o
3844 ) or inherited (
3845 .Fl x
3846 ) on the topmost in the replicated subtree. In descendant datasets, if the
3847 property is set by the send stream, it will be overridden by forcing the
3848 property to be inherited from the top‐most file system. Received properties
3849 are retained in spite of being overridden and may be restored with
3850 .Nm zfs Cm inherit Fl S .
3851 Specifying
3852 .Fl o Sy origin Ns = Ns Em snapshot
3853 is a special case because, even if
3854 .Sy origin
3855 is a read-only property and cannot be set, it's allowed to receive the send
3856 stream as a clone of the given snapshot.
3857 .Pp
3858 Raw encrypted send streams (created with
3859 .Nm zfs Cm send Fl w
3860 ) may only be received as is, and cannot be re-encrypted, decrypted, or
3861 recompressed by the receive process. Unencrypted streams can be received as
3862 encrypted datasets, either through inheritance or by specifying encryption
3863 parameters with the
3864 .Fl o
3865 options. Note that the
3866 .Sy keylocation
3867 property cannot be overridden to
3868 .Sy prompt
3869 during a receive. This is because the receive process itself is already using
3870 stdin for the send stream. Instead, the property can be overridden after the
3871 receive completes.
3872 .Pp
3873 The added security provided by raw sends adds some restrictions to the send
3874 and receive process. ZFS will not allow a mix of raw receives and non-raw
3875 receives. Specifically, any raw incremental receives that are attempted after
3876 a non-raw receive will fail. Non-raw receives do not have this restriction and,
3877 therefore, are always possible. Because of this, it is best practice to always
3878 use either raw sends for their security benefits or non-raw sends for their
3879 flexibility when working with encrypted datasets, but not a combination.
3880 .Pp
3881 The reason for this restriction stems from the inherent restrictions of the
3882 AEAD ciphers that ZFS uses to encrypt data. When using ZFS native encryption,
3883 each block of data is encrypted against a randomly generated number known as
3884 the "initialization vector" (IV), which is stored in the filesystem metadata.
3885 This number is required by the encryption algorithms whenever the data is to
3886 be decrypted. Together, all of the IVs provided for all of the blocks in a
3887 given snapshot are collectively called an "IV set". When ZFS performs a raw
3888 send, the IV set is transferred from the source to the destination in the send
3889 stream. When ZFS performs a non-raw send, the data is decrypted by the source
3890 system and re-encrypted by the destination system, creating a snapshot with
3891 effectively the same data, but a different IV set. In order for decryption to
3892 work after a raw send, ZFS must ensure that the IV set used on both the source
3893 and destination side match. When an incremental raw receive is performed on
3894 top of an existing snapshot, ZFS will check to confirm that the "from"
3895 snapshot on both the source and destination were using the same IV set,
3896 ensuring the new IV set is consistent.
3897 .Pp
3898 The name of the snapshot
3899 .Pq and file system, if a full stream is received
3900 that this subcommand creates depends on the argument type and the use of the
3901 .Fl d
3902 or
3903 .Fl e
3904 options.
3905 .Pp
3906 If the argument is a snapshot name, the specified
3907 .Ar snapshot
3908 is created.
3909 If the argument is a file system or volume name, a snapshot with the same name
3910 as the sent snapshot is created within the specified
3911 .Ar filesystem
3912 or
3913 .Ar volume .
3914 If neither of the
3915 .Fl d
3916 or
3917 .Fl e
3918 options are specified, the provided target snapshot name is used exactly as
3919 provided.
3920 .Pp
3921 The
3922 .Fl d
3923 and
3924 .Fl e
3925 options cause the file system name of the target snapshot to be determined by
3926 appending a portion of the sent snapshot's name to the specified target
3927 .Ar filesystem .
3928 If the
3929 .Fl d
3930 option is specified, all but the first element of the sent snapshot's file
3931 system path
3932 .Pq usually the pool name
3933 is used and any required intermediate file systems within the specified one are
3934 created.
3935 If the
3936 .Fl e
3937 option is specified, then only the last element of the sent snapshot's file
3938 system name
3939 .Pq i.e. the name of the source file system itself
3940 is used as the target file system name.
3941 .Bl -tag -width "-F"
3942 .It Fl F
3943 Force a rollback of the file system to the most recent snapshot before
3944 performing the receive operation.
3945 If receiving an incremental replication stream
3946 .Po for example, one generated by
3947 .Nm zfs Cm send Fl R Op Fl i Ns | Ns Fl I
3948 .Pc ,
3949 destroy snapshots and file systems that do not exist on the sending side.
3950 .It Fl d
3951 Discard the first element of the sent snapshot's file system name, using the
3952 remaining elements to determine the name of the target file system for the new
3953 snapshot as described in the paragraph above.
3954 .It Fl e
3955 Discard all but the last element of the sent snapshot's file system name, using
3956 that element to determine the name of the target file system for the new
3957 snapshot as described in the paragraph above.
3958 .It Fl h
3959 Skip the receive of holds. There is no effect if holds are not sent.
3960 .It Fl n
3961 Do not actually receive the stream.
3962 This can be useful in conjunction with the
3963 .Fl v
3964 option to verify the name the receive operation would use.
3965 .It Fl o Sy origin Ns = Ns Ar snapshot
3966 Forces the stream to be received as a clone of the given snapshot.
3967 If the stream is a full send stream, this will create the filesystem
3968 described by the stream as a clone of the specified snapshot.
3969 Which snapshot was specified will not affect the success or failure of the
3970 receive, as long as the snapshot does exist.
3971 If the stream is an incremental send stream, all the normal verification will be
3972 performed.
3973 .It Fl o Em property Ns = Ns Ar value
3974 Sets the specified property as if the command
3975 .Nm zfs Cm set Em property Ns = Ns Ar value
3976 was invoked immediately before the receive. When receiving a stream from
3977 .Nm zfs Cm send Fl R ,
3978 causes the property to be inherited by all descendant datasets, as through
3979 .Nm zfs Cm inherit Em property
3980 was run on any descendant datasets that have this property set on the
3981 sending system.
3982 .Pp
3983 Any editable property can be set at receive time. Set-once properties bound
3984 to the received data, such as
3985 .Sy normalization
3986 and
3987 .Sy casesensitivity ,
3988 cannot be set at receive time even when the datasets are newly created by
3989 .Nm zfs Cm receive .
3990 Additionally both settable properties
3991 .Sy version
3992 and
3993 .Sy volsize
3994 cannot be set at receive time.
3995 .Pp
3996 The
3997 .Fl o
3998 option may be specified multiple times, for different properties. An error
3999 results if the same property is specified in multiple
4000 .Fl o
4001 or
4002 .Fl x
4003 options.
4004 .Pp
4005 The
4006 .Fl o
4007 option may also be used to override encryption properties upon initial
4008 receive. This allows unencrypted streams to be received as encrypted datasets.
4009 To cause the received dataset (or root dataset of a recursive stream) to be
4010 received as an encryption root, specify encryption properties in the same
4011 manner as is required for
4012 .Nm
4013 .Cm create .
4014 For instance:
4015 .Bd -literal
4016 # zfs send tank/test@snap1 | zfs recv -o encryption=on -o keyformat=passphrase -o keylocation=file:///path/to/keyfile
4017 .Ed
4018 .Pp
4019 Note that
4020 .Op Fl o Ar keylocation Ns = Ns Ar prompt
4021 may not be specified here, since stdin is already being utilized for the send
4022 stream. Once the receive has completed, you can use
4023 .Nm
4024 .Cm set
4025 to change this setting after the fact. Similarly, you can receive a dataset as
4026 an encrypted child by specifying
4027 .Op Fl x Ar encryption
4028 to force the property to be inherited. Overriding encryption properties (except
4029 for
4030 .Sy keylocation Ns )
4031 is not possible with raw send streams.
4032 .It Fl s
4033 If the receive is interrupted, save the partially received state, rather
4034 than deleting it.
4035 Interruption may be due to premature termination of the stream
4036 .Po e.g. due to network failure or failure of the remote system
4037 if the stream is being read over a network connection
4038 .Pc ,
4039 a checksum error in the stream, termination of the
4040 .Nm zfs Cm receive
4041 process, or unclean shutdown of the system.
4042 .Pp
4043 The receive can be resumed with a stream generated by
4044 .Nm zfs Cm send Fl t Ar token ,
4045 where the
4046 .Ar token
4047 is the value of the
4048 .Sy receive_resume_token
4049 property of the filesystem or volume which is received into.
4050 .Pp
4051 To use this flag, the storage pool must have the
4052 .Sy extensible_dataset
4053 feature enabled.
4054 See
4055 .Xr zpool-features 5
4056 for details on ZFS feature flags.
4057 .It Fl u
4058 File system that is associated with the received stream is not mounted.
4059 .It Fl v
4060 Print verbose information about the stream and the time required to perform the
4061 receive operation.
4062 .It Fl x Em property
4063 Ensures that the effective value of the specified property after the
4064 receive is unaffected by the value of that property in the send stream (if any),
4065 as if the property had been excluded from the send stream.
4066 .Pp
4067 If the specified property is not present in the send stream, this option does
4068 nothing.
4069 .Pp
4070 If a received property needs to be overridden, the effective value will be
4071 set or inherited, depending on whether the property is inheritable or not.
4072 .Pp
4073 In the case of an incremental update,
4074 .Fl x
4075 leaves any existing local setting or explicit inheritance unchanged.
4076 .Pp
4077 All
4078 .Fl o
4079 restrictions (e.g. set-once) apply equally to
4080 .Fl x .
4081 .El
4082 .It Xo
4083 .Nm
4084 .Cm receive
4085 .Fl A
4086 .Ar filesystem Ns | Ns Ar volume
4087 .Xc
4088 Abort an interrupted
4089 .Nm zfs Cm receive Fl s ,
4090 deleting its saved partially received state.
4091 .It Xo
4092 .Nm
4093 .Cm allow
4094 .Ar filesystem Ns | Ns Ar volume
4095 .Xc
4096 Displays permissions that have been delegated on the specified filesystem or
4097 volume.
4098 See the other forms of
4099 .Nm zfs Cm allow
4100 for more information.
4101 .Pp
4102 Delegations are supported under Linux with the exception of
4103 .Sy mount ,
4104 .Sy unmount ,
4105 .Sy mountpoint ,
4106 .Sy canmount ,
4107 .Sy rename ,
4108 and
4109 .Sy share .
4110 These permissions cannot be delegated because the Linux
4111 .Xr mount 8
4112 command restricts modifications of the global namespace to the root user.
4113 .It Xo
4114 .Nm
4115 .Cm allow
4116 .Op Fl dglu
4117 .Ar user Ns | Ns Ar group Ns Oo , Ns Ar user Ns | Ns Ar group Oc Ns ...
4118 .Ar perm Ns | Ns @ Ns Ar setname Ns Oo , Ns Ar perm Ns | Ns @ Ns
4119 .Ar setname Oc Ns ...
4120 .Ar filesystem Ns | Ns Ar volume
4121 .Xc
4122 .It Xo
4123 .Nm
4124 .Cm allow
4125 .Op Fl dl
4126 .Fl e Ns | Ns Sy everyone
4127 .Ar perm Ns | Ns @ Ns Ar setname Ns Oo , Ns Ar perm Ns | Ns @ Ns
4128 .Ar setname Oc Ns ...
4129 .Ar filesystem Ns | Ns Ar volume
4130 .Xc
4131 Delegates ZFS administration permission for the file systems to non-privileged
4132 users.
4133 .Bl -tag -width "-d"
4134 .It Fl d
4135 Allow only for the descendent file systems.
4136 .It Fl e Ns | Ns Sy everyone
4137 Specifies that the permissions be delegated to everyone.
4138 .It Fl g Ar group Ns Oo , Ns Ar group Oc Ns ...
4139 Explicitly specify that permissions are delegated to the group.
4140 .It Fl l
4141 Allow
4142 .Qq locally
4143 only for the specified file system.
4144 .It Fl u Ar user Ns Oo , Ns Ar user Oc Ns ...
4145 Explicitly specify that permissions are delegated to the user.
4146 .It Ar user Ns | Ns Ar group Ns Oo , Ns Ar user Ns | Ns Ar group Oc Ns ...
4147 Specifies to whom the permissions are delegated.
4148 Multiple entities can be specified as a comma-separated list.
4149 If neither of the
4150 .Fl gu
4151 options are specified, then the argument is interpreted preferentially as the
4152 keyword
4153 .Sy everyone ,
4154 then as a user name, and lastly as a group name.
4155 To specify a user or group named
4156 .Qq everyone ,
4157 use the
4158 .Fl g
4159 or
4160 .Fl u
4161 options.
4162 To specify a group with the same name as a user, use the
4163 .Fl g
4164 options.
4165 .It Xo
4166 .Ar perm Ns | Ns @ Ns Ar setname Ns Oo , Ns Ar perm Ns | Ns @ Ns
4167 .Ar setname Oc Ns ...
4168 .Xc
4169 The permissions to delegate.
4170 Multiple permissions may be specified as a comma-separated list.
4171 Permission names are the same as ZFS subcommand and property names.
4172 See the property list below.
4173 Property set names, which begin with
4174 .Sy @ ,
4175 may be specified.
4176 See the
4177 .Fl s
4178 form below for details.
4179 .El
4180 .Pp
4181 If neither of the
4182 .Fl dl
4183 options are specified, or both are, then the permissions are allowed for the
4184 file system or volume, and all of its descendents.
4185 .Pp
4186 Permissions are generally the ability to use a ZFS subcommand or change a ZFS
4187 property.
4188 The following permissions are available:
4189 .Bd -literal
4190 NAME TYPE NOTES
4191 allow subcommand Must also have the permission that is
4192 being allowed
4193 clone subcommand Must also have the 'create' ability and
4194 'mount' ability in the origin file system
4195 create subcommand Must also have the 'mount' ability.
4196 Must also have the 'refreservation' ability to
4197 create a non-sparse volume.
4198 destroy subcommand Must also have the 'mount' ability
4199 diff subcommand Allows lookup of paths within a dataset
4200 given an object number, and the ability
4201 to create snapshots necessary to
4202 'zfs diff'.
4203 load-key subcommand Allows loading and unloading of encryption key
4204 (see 'zfs load-key' and 'zfs unload-key').
4205 change-key subcommand Allows changing an encryption key via
4206 'zfs change-key'.
4207 mount subcommand Allows mount/umount of ZFS datasets
4208 promote subcommand Must also have the 'mount' and 'promote'
4209 ability in the origin file system
4210 receive subcommand Must also have the 'mount' and 'create'
4211 ability
4212 rename subcommand Must also have the 'mount' and 'create'
4213 ability in the new parent
4214 rollback subcommand Must also have the 'mount' ability
4215 send subcommand
4216 share subcommand Allows sharing file systems over NFS
4217 or SMB protocols
4218 snapshot subcommand Must also have the 'mount' ability
4219
4220 groupquota other Allows accessing any groupquota@...
4221 property
4222 groupused other Allows reading any groupused@... property
4223 userprop other Allows changing any user property
4224 userquota other Allows accessing any userquota@...
4225 property
4226 userused other Allows reading any userused@... property
4227 projectobjquota other Allows accessing any projectobjquota@...
4228 property
4229 projectquota other Allows accessing any projectquota@... property
4230 projectobjused other Allows reading any projectobjused@... property
4231 projectused other Allows reading any projectused@... property
4232
4233 aclinherit property
4234 acltype property
4235 atime property
4236 canmount property
4237 casesensitivity property
4238 checksum property
4239 compression property
4240 copies property
4241 devices property
4242 exec property
4243 filesystem_limit property
4244 mountpoint property
4245 nbmand property
4246 normalization property
4247 primarycache property
4248 quota property
4249 readonly property
4250 recordsize property
4251 refquota property
4252 refreservation property
4253 reservation property
4254 secondarycache property
4255 setuid property
4256 sharenfs property
4257 sharesmb property
4258 snapdir property
4259 snapshot_limit property
4260 utf8only property
4261 version property
4262 volblocksize property
4263 volsize property
4264 vscan property
4265 xattr property
4266 zoned property
4267 .Ed
4268 .It Xo
4269 .Nm
4270 .Cm allow
4271 .Fl c
4272 .Ar perm Ns | Ns @ Ns Ar setname Ns Oo , Ns Ar perm Ns | Ns @ Ns
4273 .Ar setname Oc Ns ...
4274 .Ar filesystem Ns | Ns Ar volume
4275 .Xc
4276 Sets
4277 .Qq create time
4278 permissions.
4279 These permissions are granted
4280 .Pq locally
4281 to the creator of any newly-created descendent file system.
4282 .It Xo
4283 .Nm
4284 .Cm allow
4285 .Fl s No @ Ns Ar setname
4286 .Ar perm Ns | Ns @ Ns Ar setname Ns Oo , Ns Ar perm Ns | Ns @ Ns
4287 .Ar setname Oc Ns ...
4288 .Ar filesystem Ns | Ns Ar volume
4289 .Xc
4290 Defines or adds permissions to a permission set.
4291 The set can be used by other
4292 .Nm zfs Cm allow
4293 commands for the specified file system and its descendents.
4294 Sets are evaluated dynamically, so changes to a set are immediately reflected.
4295 Permission sets follow the same naming restrictions as ZFS file systems, but the
4296 name must begin with
4297 .Sy @ ,
4298 and can be no more than 64 characters long.
4299 .It Xo
4300 .Nm
4301 .Cm unallow
4302 .Op Fl dglru
4303 .Ar user Ns | Ns Ar group Ns Oo , Ns Ar user Ns | Ns Ar group Oc Ns ...
4304 .Oo Ar perm Ns | Ns @ Ns Ar setname Ns Oo , Ns Ar perm Ns | Ns @ Ns
4305 .Ar setname Oc Ns ... Oc
4306 .Ar filesystem Ns | Ns Ar volume
4307 .Xc
4308 .It Xo
4309 .Nm
4310 .Cm unallow
4311 .Op Fl dlr
4312 .Fl e Ns | Ns Sy everyone
4313 .Oo Ar perm Ns | Ns @ Ns Ar setname Ns Oo , Ns Ar perm Ns | Ns @ Ns
4314 .Ar setname Oc Ns ... Oc
4315 .Ar filesystem Ns | Ns Ar volume
4316 .Xc
4317 .It Xo
4318 .Nm
4319 .Cm unallow
4320 .Op Fl r
4321 .Fl c
4322 .Oo Ar perm Ns | Ns @ Ns Ar setname Ns Oo , Ns Ar perm Ns | Ns @ Ns
4323 .Ar setname Oc Ns ... Oc
4324 .Ar filesystem Ns | Ns Ar volume
4325 .Xc
4326 Removes permissions that were granted with the
4327 .Nm zfs Cm allow
4328 command.
4329 No permissions are explicitly denied, so other permissions granted are still in
4330 effect.
4331 For example, if the permission is granted by an ancestor.
4332 If no permissions are specified, then all permissions for the specified
4333 .Ar user ,
4334 .Ar group ,
4335 or
4336 .Sy everyone
4337 are removed.
4338 Specifying
4339 .Sy everyone
4340 .Po or using the
4341 .Fl e
4342 option
4343 .Pc
4344 only removes the permissions that were granted to everyone, not all permissions
4345 for every user and group.
4346 See the
4347 .Nm zfs Cm allow
4348 command for a description of the
4349 .Fl ldugec
4350 options.
4351 .Bl -tag -width "-r"
4352 .It Fl r
4353 Recursively remove the permissions from this file system and all descendents.
4354 .El
4355 .It Xo
4356 .Nm
4357 .Cm unallow
4358 .Op Fl r
4359 .Fl s No @ Ns Ar setname
4360 .Oo Ar perm Ns | Ns @ Ns Ar setname Ns Oo , Ns Ar perm Ns | Ns @ Ns
4361 .Ar setname Oc Ns ... Oc
4362 .Ar filesystem Ns | Ns Ar volume
4363 .Xc
4364 Removes permissions from a permission set.
4365 If no permissions are specified, then all permissions are removed, thus removing
4366 the set entirely.
4367 .It Xo
4368 .Nm
4369 .Cm hold
4370 .Op Fl r
4371 .Ar tag Ar snapshot Ns ...
4372 .Xc
4373 Adds a single reference, named with the
4374 .Ar tag
4375 argument, to the specified snapshot or snapshots.
4376 Each snapshot has its own tag namespace, and tags must be unique within that
4377 space.
4378 .Pp
4379 If a hold exists on a snapshot, attempts to destroy that snapshot by using the
4380 .Nm zfs Cm destroy
4381 command return
4382 .Er EBUSY .
4383 .Bl -tag -width "-r"
4384 .It Fl r
4385 Specifies that a hold with the given tag is applied recursively to the snapshots
4386 of all descendent file systems.
4387 .El
4388 .It Xo
4389 .Nm
4390 .Cm holds
4391 .Op Fl rH
4392 .Ar snapshot Ns ...
4393 .Xc
4394 Lists all existing user references for the given snapshot or snapshots.
4395 .Bl -tag -width "-r"
4396 .It Fl r
4397 Lists the holds that are set on the named descendent snapshots, in addition to
4398 listing the holds on the named snapshot.
4399 .It Fl H
4400 Do not print headers, use tab-delimited output.
4401 .El
4402 .It Xo
4403 .Nm
4404 .Cm release
4405 .Op Fl r
4406 .Ar tag Ar snapshot Ns ...
4407 .Xc
4408 Removes a single reference, named with the
4409 .Ar tag
4410 argument, from the specified snapshot or snapshots.
4411 The tag must already exist for each snapshot.
4412 If a hold exists on a snapshot, attempts to destroy that snapshot by using the
4413 .Nm zfs Cm destroy
4414 command return
4415 .Er EBUSY .
4416 .Bl -tag -width "-r"
4417 .It Fl r
4418 Recursively releases a hold with the given tag on the snapshots of all
4419 descendent file systems.
4420 .El
4421 .It Xo
4422 .Nm
4423 .Cm diff
4424 .Op Fl FHt
4425 .Ar snapshot Ar snapshot Ns | Ns Ar filesystem
4426 .Xc
4427 Display the difference between a snapshot of a given filesystem and another
4428 snapshot of that filesystem from a later time or the current contents of the
4429 filesystem.
4430 The first column is a character indicating the type of change, the other columns
4431 indicate pathname, new pathname
4432 .Pq in case of rename ,
4433 change in link count, and optionally file type and/or change time.
4434 The types of change are:
4435 .Bd -literal
4436 - The path has been removed
4437 + The path has been created
4438 M The path has been modified
4439 R The path has been renamed
4440 .Ed
4441 .Bl -tag -width "-F"
4442 .It Fl F
4443 Display an indication of the type of file, in a manner similar to the
4444 .Fl
4445 option of
4446 .Xr ls 1 .
4447 .Bd -literal
4448 B Block device
4449 C Character device
4450 / Directory
4451 > Door
4452 | Named pipe
4453 @ Symbolic link
4454 P Event port
4455 = Socket
4456 F Regular file
4457 .Ed
4458 .It Fl H
4459 Give more parsable tab-separated output, without header lines and without
4460 arrows.
4461 .It Fl t
4462 Display the path's inode change time as the first column of output.
4463 .El
4464 .It Xo
4465 .Nm
4466 .Cm program
4467 .Op Fl jn
4468 .Op Fl t Ar instruction-limit
4469 .Op Fl m Ar memory-limit
4470 .Ar pool script
4471 .Op Ar arg1 No ...
4472 .Xc
4473 Executes
4474 .Ar script
4475 as a ZFS channel program on
4476 .Ar pool .
4477 The ZFS channel
4478 program interface allows ZFS administrative operations to be run
4479 programmatically via a Lua script.
4480 The entire script is executed atomically, with no other administrative
4481 operations taking effect concurrently.
4482 A library of ZFS calls is made available to channel program scripts.
4483 Channel programs may only be run with root privileges.
4484 .sp
4485 For full documentation of the ZFS channel program interface, see the manual
4486 page for
4487 .Xr zfs-program 8 .
4488 .Bl -tag -width ""
4489 .It Fl j
4490 Display channel program output in JSON format. When this flag is specified and
4491 standard output is empty - channel program encountered an error. The details of
4492 such an error will be printed to standard error in plain text.
4493 .It Fl n
4494 Executes a read-only channel program, which runs faster.
4495 The program cannot change on-disk state by calling functions from
4496 the zfs.sync submodule.
4497 The program can be used to gather information such as properties and
4498 determining if changes would succeed (zfs.check.*).
4499 Without this flag, all pending changes must be synced to disk before
4500 a channel program can complete.
4501 .It Fl t Ar instruction-limit
4502 Limit the number of Lua instructions to execute.
4503 If a channel program executes more than the specified number of instructions,
4504 it will be stopped and an error will be returned.
4505 The default limit is 10 million instructions, and it can be set to a maximum of
4506 100 million instructions.
4507 .It Fl m Ar memory-limit
4508 Memory limit, in bytes.
4509 If a channel program attempts to allocate more memory than the given limit,
4510 it will be stopped and an error returned.
4511 The default memory limit is 10 MB, and can be set to a maximum of 100 MB.
4512 .sp
4513 All remaining argument strings are passed directly to the channel program as
4514 arguments.
4515 See
4516 .Xr zfs-program 8
4517 for more information.
4518 .El
4519 .It Xo
4520 .Nm
4521 .Cm load-key
4522 .Op Fl nr
4523 .Op Fl L Ar keylocation
4524 .Fl a | Ar filesystem
4525 .Xc
4526 Load the key for
4527 .Ar filesystem ,
4528 allowing it and all children that inherit the
4529 .Sy keylocation
4530 property to be accessed. The key will be expected in the format specified by the
4531 .Sy keyformat
4532 and location specified by the
4533 .Sy keylocation
4534 property. Note that if the
4535 .Sy keylocation
4536 is set to
4537 .Sy prompt
4538 the terminal will interactively wait for the key to be entered. Loading a key
4539 will not automatically mount the dataset. If that functionality is desired,
4540 .Nm zfs Cm mount Sy -l
4541 will ask for the key and mount the dataset. Once the key is loaded the
4542 .Sy keystatus
4543 property will become
4544 .Sy available .
4545 .Bl -tag -width "-r"
4546 .It Fl r
4547 Recursively loads the keys for the specified filesystem and all descendent
4548 encryption roots.
4549 .It Fl a
4550 Loads the keys for all encryption roots in all imported pools.
4551 .It Fl n
4552 Do a dry-run
4553 .Pq Qq No-op
4554 load-key. This will cause zfs to simply check that the
4555 provided key is correct. This command may be run even if the key is already
4556 loaded.
4557 .It Fl L Ar keylocation
4558 Use
4559 .Ar keylocation
4560 instead of the
4561 .Sy keylocation
4562 property. This will not change the value of the property on the dataset. Note
4563 that if used with either
4564 .Fl r
4565 or
4566 .Fl a ,
4567 .Ar keylocation
4568 may only be given as
4569 .Sy prompt .
4570 .El
4571 .It Xo
4572 .Nm
4573 .Cm unload-key
4574 .Op Fl r
4575 .Fl a | Ar filesystem
4576 .Xc
4577 Unloads a key from ZFS, removing the ability to access the dataset and all of
4578 its children that inherit the
4579 .Sy keylocation
4580 property. This requires that the dataset is not currently open or mounted. Once
4581 the key is unloaded the
4582 .Sy keystatus
4583 property will become
4584 .Sy unavailable .
4585 .Bl -tag -width "-r"
4586 .It Fl r
4587 Recursively unloads the keys for the specified filesystem and all descendent
4588 encryption roots.
4589 .It Fl a
4590 Unloads the keys for all encryption roots in all imported pools.
4591 .El
4592 .It Xo
4593 .Nm
4594 .Cm change-key
4595 .Op Fl l
4596 .Op Fl o Ar keylocation Ns = Ns Ar value
4597 .Op Fl o Ar keyformat Ns = Ns Ar value
4598 .Op Fl o Ar pbkdf2iters Ns = Ns Ar value
4599 .Ar filesystem
4600 .Xc
4601 .It Xo
4602 .Nm
4603 .Cm change-key
4604 .Fl i
4605 .Op Fl l
4606 .Ar filesystem
4607 .Xc
4608 Allows a user to change the encryption key used to access a dataset. This
4609 command requires that the existing key for the dataset is already loaded into
4610 ZFS. This command may also be used to change the
4611 .Sy keylocation ,
4612 .Sy keyformat ,
4613 and
4614 .Sy pbkdf2iters
4615 properties as needed. If the dataset was not previously an encryption root it
4616 will become one. Alternatively, the
4617 .Fl i
4618 flag may be provided to cause an encryption root to inherit the parent's key
4619 instead.
4620 .Bl -tag -width "-r"
4621 .It Fl l
4622 Ensures the key is loaded before attempting to change the key. This is
4623 effectively equivalent to
4624 .Qq Nm zfs Cm load-key Ar filesystem ; Nm zfs Cm change-key Ar filesystem
4625 .It Fl o Ar property Ns = Ns Ar value
4626 Allows the user to set encryption key properties (
4627 .Sy keyformat ,
4628 .Sy keylocation ,
4629 and
4630 .Sy pbkdf2iters
4631 ) while changing the key. This is the only way to alter
4632 .Sy keyformat
4633 and
4634 .Sy pbkdf2iters
4635 after the dataset has been created.
4636 .It Fl i
4637 Indicates that zfs should make
4638 .Ar filesystem
4639 inherit the key of its parent. Note that this command can only be run on an
4640 encryption root that has an encrypted parent.
4641 .El
4642 .It Xo
4643 .Nm
4644 .Cm version
4645 .Xc
4646 Displays the software version of the
4647 .Nm
4648 userland utility and the zfs kernel module.
4649 .El
4650 .Sh EXIT STATUS
4651 The
4652 .Nm
4653 utility exits 0 on success, 1 if an error occurs, and 2 if invalid command line
4654 options were specified.
4655 .Sh EXAMPLES
4656 .Bl -tag -width ""
4657 .It Sy Example 1 No Creating a ZFS File System Hierarchy
4658 The following commands create a file system named
4659 .Em pool/home
4660 and a file system named
4661 .Em pool/home/bob .
4662 The mount point
4663 .Pa /export/home
4664 is set for the parent file system, and is automatically inherited by the child
4665 file system.
4666 .Bd -literal
4667 # zfs create pool/home
4668 # zfs set mountpoint=/export/home pool/home
4669 # zfs create pool/home/bob
4670 .Ed
4671 .It Sy Example 2 No Creating a ZFS Snapshot
4672 The following command creates a snapshot named
4673 .Sy yesterday .
4674 This snapshot is mounted on demand in the
4675 .Pa .zfs/snapshot
4676 directory at the root of the
4677 .Em pool/home/bob
4678 file system.
4679 .Bd -literal
4680 # zfs snapshot pool/home/bob@yesterday
4681 .Ed
4682 .It Sy Example 3 No Creating and Destroying Multiple Snapshots
4683 The following command creates snapshots named
4684 .Sy yesterday
4685 of
4686 .Em pool/home
4687 and all of its descendent file systems.
4688 Each snapshot is mounted on demand in the
4689 .Pa .zfs/snapshot
4690 directory at the root of its file system.
4691 The second command destroys the newly created snapshots.
4692 .Bd -literal
4693 # zfs snapshot -r pool/home@yesterday
4694 # zfs destroy -r pool/home@yesterday
4695 .Ed
4696 .It Sy Example 4 No Disabling and Enabling File System Compression
4697 The following command disables the
4698 .Sy compression
4699 property for all file systems under
4700 .Em pool/home .
4701 The next command explicitly enables
4702 .Sy compression
4703 for
4704 .Em pool/home/anne .
4705 .Bd -literal
4706 # zfs set compression=off pool/home
4707 # zfs set compression=on pool/home/anne
4708 .Ed
4709 .It Sy Example 5 No Listing ZFS Datasets
4710 The following command lists all active file systems and volumes in the system.
4711 Snapshots are displayed if the
4712 .Sy listsnaps
4713 property is
4714 .Sy on .
4715 The default is
4716 .Sy off .
4717 See
4718 .Xr zpool 8
4719 for more information on pool properties.
4720 .Bd -literal
4721 # zfs list
4722 NAME USED AVAIL REFER MOUNTPOINT
4723 pool 450K 457G 18K /pool
4724 pool/home 315K 457G 21K /export/home
4725 pool/home/anne 18K 457G 18K /export/home/anne
4726 pool/home/bob 276K 457G 276K /export/home/bob
4727 .Ed
4728 .It Sy Example 6 No Setting a Quota on a ZFS File System
4729 The following command sets a quota of 50 Gbytes for
4730 .Em pool/home/bob .
4731 .Bd -literal
4732 # zfs set quota=50G pool/home/bob
4733 .Ed
4734 .It Sy Example 7 No Listing ZFS Properties
4735 The following command lists all properties for
4736 .Em pool/home/bob .
4737 .Bd -literal
4738 # zfs get all pool/home/bob
4739 NAME PROPERTY VALUE SOURCE
4740 pool/home/bob type filesystem -
4741 pool/home/bob creation Tue Jul 21 15:53 2009 -
4742 pool/home/bob used 21K -
4743 pool/home/bob available 20.0G -
4744 pool/home/bob referenced 21K -
4745 pool/home/bob compressratio 1.00x -
4746 pool/home/bob mounted yes -
4747 pool/home/bob quota 20G local
4748 pool/home/bob reservation none default
4749 pool/home/bob recordsize 128K default
4750 pool/home/bob mountpoint /pool/home/bob default
4751 pool/home/bob sharenfs off default
4752 pool/home/bob checksum on default
4753 pool/home/bob compression on local
4754 pool/home/bob atime on default
4755 pool/home/bob devices on default
4756 pool/home/bob exec on default
4757 pool/home/bob setuid on default
4758 pool/home/bob readonly off default
4759 pool/home/bob zoned off default
4760 pool/home/bob snapdir hidden default
4761 pool/home/bob acltype off default
4762 pool/home/bob aclinherit restricted default
4763 pool/home/bob canmount on default
4764 pool/home/bob xattr on default
4765 pool/home/bob copies 1 default
4766 pool/home/bob version 4 -
4767 pool/home/bob utf8only off -
4768 pool/home/bob normalization none -
4769 pool/home/bob casesensitivity sensitive -
4770 pool/home/bob vscan off default
4771 pool/home/bob nbmand off default
4772 pool/home/bob sharesmb off default
4773 pool/home/bob refquota none default
4774 pool/home/bob refreservation none default
4775 pool/home/bob primarycache all default
4776 pool/home/bob secondarycache all default
4777 pool/home/bob usedbysnapshots 0 -
4778 pool/home/bob usedbydataset 21K -
4779 pool/home/bob usedbychildren 0 -
4780 pool/home/bob usedbyrefreservation 0 -
4781 .Ed
4782 .Pp
4783 The following command gets a single property value.
4784 .Bd -literal
4785 # zfs get -H -o value compression pool/home/bob
4786 on
4787 .Ed
4788 The following command lists all properties with local settings for
4789 .Em pool/home/bob .
4790 .Bd -literal
4791 # zfs get -r -s local -o name,property,value all pool/home/bob
4792 NAME PROPERTY VALUE
4793 pool/home/bob quota 20G
4794 pool/home/bob compression on
4795 .Ed
4796 .It Sy Example 8 No Rolling Back a ZFS File System
4797 The following command reverts the contents of
4798 .Em pool/home/anne
4799 to the snapshot named
4800 .Sy yesterday ,
4801 deleting all intermediate snapshots.
4802 .Bd -literal
4803 # zfs rollback -r pool/home/anne@yesterday
4804 .Ed
4805 .It Sy Example 9 No Creating a ZFS Clone
4806 The following command creates a writable file system whose initial contents are
4807 the same as
4808 .Em pool/home/bob@yesterday .
4809 .Bd -literal
4810 # zfs clone pool/home/bob@yesterday pool/clone
4811 .Ed
4812 .It Sy Example 10 No Promoting a ZFS Clone
4813 The following commands illustrate how to test out changes to a file system, and
4814 then replace the original file system with the changed one, using clones, clone
4815 promotion, and renaming:
4816 .Bd -literal
4817 # zfs create pool/project/production
4818 populate /pool/project/production with data
4819 # zfs snapshot pool/project/production@today
4820 # zfs clone pool/project/production@today pool/project/beta
4821 make changes to /pool/project/beta and test them
4822 # zfs promote pool/project/beta
4823 # zfs rename pool/project/production pool/project/legacy
4824 # zfs rename pool/project/beta pool/project/production
4825 once the legacy version is no longer needed, it can be destroyed
4826 # zfs destroy pool/project/legacy
4827 .Ed
4828 .It Sy Example 11 No Inheriting ZFS Properties
4829 The following command causes
4830 .Em pool/home/bob
4831 and
4832 .Em pool/home/anne
4833 to inherit the
4834 .Sy checksum
4835 property from their parent.
4836 .Bd -literal
4837 # zfs inherit checksum pool/home/bob pool/home/anne
4838 .Ed
4839 .It Sy Example 12 No Remotely Replicating ZFS Data
4840 The following commands send a full stream and then an incremental stream to a
4841 remote machine, restoring them into
4842 .Em poolB/received/fs@a
4843 and
4844 .Em poolB/received/fs@b ,
4845 respectively.
4846 .Em poolB
4847 must contain the file system
4848 .Em poolB/received ,
4849 and must not initially contain
4850 .Em poolB/received/fs .
4851 .Bd -literal
4852 # zfs send pool/fs@a | \e
4853 ssh host zfs receive poolB/received/fs@a
4854 # zfs send -i a pool/fs@b | \e
4855 ssh host zfs receive poolB/received/fs
4856 .Ed
4857 .It Sy Example 13 No Using the zfs receive -d Option
4858 The following command sends a full stream of
4859 .Em poolA/fsA/fsB@snap
4860 to a remote machine, receiving it into
4861 .Em poolB/received/fsA/fsB@snap .
4862 The
4863 .Em fsA/fsB@snap
4864 portion of the received snapshot's name is determined from the name of the sent
4865 snapshot.
4866 .Em poolB
4867 must contain the file system
4868 .Em poolB/received .
4869 If
4870 .Em poolB/received/fsA
4871 does not exist, it is created as an empty file system.
4872 .Bd -literal
4873 # zfs send poolA/fsA/fsB@snap | \e
4874 ssh host zfs receive -d poolB/received
4875 .Ed
4876 .It Sy Example 14 No Setting User Properties
4877 The following example sets the user-defined
4878 .Sy com.example:department
4879 property for a dataset.
4880 .Bd -literal
4881 # zfs set com.example:department=12345 tank/accounting
4882 .Ed
4883 .It Sy Example 15 No Performing a Rolling Snapshot
4884 The following example shows how to maintain a history of snapshots with a
4885 consistent naming scheme.
4886 To keep a week's worth of snapshots, the user destroys the oldest snapshot,
4887 renames the remaining snapshots, and then creates a new snapshot, as follows:
4888 .Bd -literal
4889 # zfs destroy -r pool/users@7daysago
4890 # zfs rename -r pool/users@6daysago @7daysago
4891 # zfs rename -r pool/users@5daysago @6daysago
4892 # zfs rename -r pool/users@4daysago @5daysago
4893 # zfs rename -r pool/users@3daysago @4daysago
4894 # zfs rename -r pool/users@2daysago @3daysago
4895 # zfs rename -r pool/users@yesterday @2daysago
4896 # zfs rename -r pool/users@today @yesterday
4897 # zfs snapshot -r pool/users@today
4898 .Ed
4899 .It Sy Example 16 No Setting sharenfs Property Options on a ZFS File System
4900 The following commands show how to set
4901 .Sy sharenfs
4902 property options to enable
4903 .Sy rw
4904 access for a set of
4905 .Sy IP
4906 addresses and to enable root access for system
4907 .Sy neo
4908 on the
4909 .Em tank/home
4910 file system.
4911 .Bd -literal
4912 # zfs set sharenfs='rw=@123.123.0.0/16,root=neo' tank/home
4913 .Ed
4914 .Pp
4915 If you are using
4916 .Sy DNS
4917 for host name resolution, specify the fully qualified hostname.
4918 .It Sy Example 17 No Delegating ZFS Administration Permissions on a ZFS Dataset
4919 The following example shows how to set permissions so that user
4920 .Sy cindys
4921 can create, destroy, mount, and take snapshots on
4922 .Em tank/cindys .
4923 The permissions on
4924 .Em tank/cindys
4925 are also displayed.
4926 .Bd -literal
4927 # zfs allow cindys create,destroy,mount,snapshot tank/cindys
4928 # zfs allow tank/cindys
4929 ---- Permissions on tank/cindys --------------------------------------
4930 Local+Descendent permissions:
4931 user cindys create,destroy,mount,snapshot
4932 .Ed
4933 .Pp
4934 Because the
4935 .Em tank/cindys
4936 mount point permission is set to 755 by default, user
4937 .Sy cindys
4938 will be unable to mount file systems under
4939 .Em tank/cindys .
4940 Add an ACE similar to the following syntax to provide mount point access:
4941 .Bd -literal
4942 # chmod A+user:cindys:add_subdirectory:allow /tank/cindys
4943 .Ed
4944 .It Sy Example 18 No Delegating Create Time Permissions on a ZFS Dataset
4945 The following example shows how to grant anyone in the group
4946 .Sy staff
4947 to create file systems in
4948 .Em tank/users .
4949 This syntax also allows staff members to destroy their own file systems, but not
4950 destroy anyone else's file system.
4951 The permissions on
4952 .Em tank/users
4953 are also displayed.
4954 .Bd -literal
4955 # zfs allow staff create,mount tank/users
4956 # zfs allow -c destroy tank/users
4957 # zfs allow tank/users
4958 ---- Permissions on tank/users ---------------------------------------
4959 Permission sets:
4960 destroy
4961 Local+Descendent permissions:
4962 group staff create,mount
4963 .Ed
4964 .It Sy Example 19 No Defining and Granting a Permission Set on a ZFS Dataset
4965 The following example shows how to define and grant a permission set on the
4966 .Em tank/users
4967 file system.
4968 The permissions on
4969 .Em tank/users
4970 are also displayed.
4971 .Bd -literal
4972 # zfs allow -s @pset create,destroy,snapshot,mount tank/users
4973 # zfs allow staff @pset tank/users
4974 # zfs allow tank/users
4975 ---- Permissions on tank/users ---------------------------------------
4976 Permission sets:
4977 @pset create,destroy,mount,snapshot
4978 Local+Descendent permissions:
4979 group staff @pset
4980 .Ed
4981 .It Sy Example 20 No Delegating Property Permissions on a ZFS Dataset
4982 The following example shows to grant the ability to set quotas and reservations
4983 on the
4984 .Em users/home
4985 file system.
4986 The permissions on
4987 .Em users/home
4988 are also displayed.
4989 .Bd -literal
4990 # zfs allow cindys quota,reservation users/home
4991 # zfs allow users/home
4992 ---- Permissions on users/home ---------------------------------------
4993 Local+Descendent permissions:
4994 user cindys quota,reservation
4995 cindys% zfs set quota=10G users/home/marks
4996 cindys% zfs get quota users/home/marks
4997 NAME PROPERTY VALUE SOURCE
4998 users/home/marks quota 10G local
4999 .Ed
5000 .It Sy Example 21 No Removing ZFS Delegated Permissions on a ZFS Dataset
5001 The following example shows how to remove the snapshot permission from the
5002 .Sy staff
5003 group on the
5004 .Em tank/users
5005 file system.
5006 The permissions on
5007 .Em tank/users
5008 are also displayed.
5009 .Bd -literal
5010 # zfs unallow staff snapshot tank/users
5011 # zfs allow tank/users
5012 ---- Permissions on tank/users ---------------------------------------
5013 Permission sets:
5014 @pset create,destroy,mount,snapshot
5015 Local+Descendent permissions:
5016 group staff @pset
5017 .Ed
5018 .It Sy Example 22 No Showing the differences between a snapshot and a ZFS Dataset
5019 The following example shows how to see what has changed between a prior
5020 snapshot of a ZFS dataset and its current state.
5021 The
5022 .Fl F
5023 option is used to indicate type information for the files affected.
5024 .Bd -literal
5025 # zfs diff -F tank/test@before tank/test
5026 M / /tank/test/
5027 M F /tank/test/linked (+1)
5028 R F /tank/test/oldname -> /tank/test/newname
5029 - F /tank/test/deleted
5030 + F /tank/test/created
5031 M F /tank/test/modified
5032 .Ed
5033 .It Sy Example 23 No Creating a bookmark
5034 The following example create a bookmark to a snapshot. This bookmark
5035 can then be used instead of snapshot in send streams.
5036 .Bd -literal
5037 # zfs bookmark rpool@snapshot rpool#bookmark
5038 .Ed
5039 .It Sy Example 24 No Setting sharesmb Property Options on a ZFS File System
5040 The following example show how to share SMB filesystem through ZFS. Note that
5041 that a user and his/her password must be given.
5042 .Bd -literal
5043 # smbmount //127.0.0.1/share_tmp /mnt/tmp \\
5044 -o user=workgroup/turbo,password=obrut,uid=1000
5045 .Ed
5046 .Pp
5047 Minimal
5048 .Em /etc/samba/smb.conf
5049 configuration required:
5050 .Pp
5051 Samba will need to listen to 'localhost' (127.0.0.1) for the ZFS utilities to
5052 communicate with Samba. This is the default behavior for most Linux
5053 distributions.
5054 .Pp
5055 Samba must be able to authenticate a user. This can be done in a number of
5056 ways, depending on if using the system password file, LDAP or the Samba
5057 specific smbpasswd file. How to do this is outside the scope of this manual.
5058 Please refer to the
5059 .Xr smb.conf 5
5060 man page for more information.
5061 .Pp
5062 See the
5063 .Sy USERSHARE section
5064 of the
5065 .Xr smb.conf 5
5066 man page for all configuration options in case you need to modify any options
5067 to the share afterwards. Do note that any changes done with the
5068 .Xr net 8
5069 command will be undone if the share is ever unshared (such as at a reboot etc).
5070 .El
5071 .Sh INTERFACE STABILITY
5072 .Sy Committed .
5073 .Sh SEE ALSO
5074 .Xr attr 1 ,
5075 .Xr gzip 1 ,
5076 .Xr ssh 1 ,
5077 .Xr chmod 2 ,
5078 .Xr fsync 2 ,
5079 .Xr stat 2 ,
5080 .Xr write 2 ,
5081 .Xr acl 5 ,
5082 .Xr attributes 5 ,
5083 .Xr exports 5 ,
5084 .Xr exportfs 8 ,
5085 .Xr mount 8 ,
5086 .Xr net 8 ,
5087 .Xr selinux 8 ,
5088 .Xr zpool 8