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1 [[chapter_pveceph]]
2 ifdef::manvolnum[]
3 pveceph(1)
4 ==========
5 :pve-toplevel:
6
7 NAME
8 ----
9
10 pveceph - Manage Ceph Services on Proxmox VE Nodes
11
12 SYNOPSIS
13 --------
14
15 include::pveceph.1-synopsis.adoc[]
16
17 DESCRIPTION
18 -----------
19 endif::manvolnum[]
20 ifndef::manvolnum[]
21 Manage Ceph Services on Proxmox VE Nodes
22 ========================================
23 :pve-toplevel:
24 endif::manvolnum[]
25
26 [thumbnail="screenshot/gui-ceph-status.png"]
27
28 {pve} unifies your compute and storage systems, i.e. you can use the same
29 physical nodes within a cluster for both computing (processing VMs and
30 containers) and replicated storage. The traditional silos of compute and
31 storage resources can be wrapped up into a single hyper-converged appliance.
32 Separate storage networks (SANs) and connections via network attached storages
33 (NAS) disappear. With the integration of Ceph, an open source software-defined
34 storage platform, {pve} has the ability to run and manage Ceph storage directly
35 on the hypervisor nodes.
36
37 Ceph is a distributed object store and file system designed to provide
38 excellent performance, reliability and scalability.
39
40 .Some advantages of Ceph on {pve} are:
41 - Easy setup and management with CLI and GUI support
42 - Thin provisioning
43 - Snapshots support
44 - Self healing
45 - Scalable to the exabyte level
46 - Setup pools with different performance and redundancy characteristics
47 - Data is replicated, making it fault tolerant
48 - Runs on economical commodity hardware
49 - No need for hardware RAID controllers
50 - Open source
51
52 For small to mid sized deployments, it is possible to install a Ceph server for
53 RADOS Block Devices (RBD) directly on your {pve} cluster nodes, see
54 xref:ceph_rados_block_devices[Ceph RADOS Block Devices (RBD)]. Recent
55 hardware has plenty of CPU power and RAM, so running storage services
56 and VMs on the same node is possible.
57
58 To simplify management, we provide 'pveceph' - a tool to install and
59 manage {ceph} services on {pve} nodes.
60
61 .Ceph consists of a couple of Daemons footnote:[Ceph intro http://docs.ceph.com/docs/luminous/start/intro/], for use as a RBD storage:
62 - Ceph Monitor (ceph-mon)
63 - Ceph Manager (ceph-mgr)
64 - Ceph OSD (ceph-osd; Object Storage Daemon)
65
66 TIP: We highly recommend to get familiar with Ceph's architecture
67 footnote:[Ceph architecture http://docs.ceph.com/docs/luminous/architecture/]
68 and vocabulary
69 footnote:[Ceph glossary http://docs.ceph.com/docs/luminous/glossary].
70
71
72 Precondition
73 ------------
74
75 To build a hyper-converged Proxmox + Ceph Cluster there should be at least
76 three (preferably) identical servers for the setup.
77
78 Check also the recommendations from
79 http://docs.ceph.com/docs/luminous/start/hardware-recommendations/[Ceph's website].
80
81 .CPU
82 Higher CPU core frequency reduce latency and should be preferred. As a simple
83 rule of thumb, you should assign a CPU core (or thread) to each Ceph service to
84 provide enough resources for stable and durable Ceph performance.
85
86 .Memory
87 Especially in a hyper-converged setup, the memory consumption needs to be
88 carefully monitored. In addition to the intended workload from virtual machines
89 and container, Ceph needs enough memory available to provide good and stable
90 performance. As a rule of thumb, for roughly 1 TiB of data, 1 GiB of memory
91 will be used by an OSD. OSD caching will use additional memory.
92
93 .Network
94 We recommend a network bandwidth of at least 10 GbE or more, which is used
95 exclusively for Ceph. A meshed network setup
96 footnote:[Full Mesh Network for Ceph {webwiki-url}Full_Mesh_Network_for_Ceph_Server]
97 is also an option if there are no 10 GbE switches available.
98
99 The volume of traffic, especially during recovery, will interfere with other
100 services on the same network and may even break the {pve} cluster stack.
101
102 Further, estimate your bandwidth needs. While one HDD might not saturate a 1 Gb
103 link, multiple HDD OSDs per node can, and modern NVMe SSDs will even saturate
104 10 Gbps of bandwidth quickly. Deploying a network capable of even more bandwith
105 will ensure that it isn't your bottleneck and won't be anytime soon, 25, 40 or
106 even 100 GBps are possible.
107
108 .Disks
109 When planning the size of your Ceph cluster, it is important to take the
110 recovery time into consideration. Especially with small clusters, the recovery
111 might take long. It is recommended that you use SSDs instead of HDDs in small
112 setups to reduce recovery time, minimizing the likelihood of a subsequent
113 failure event during recovery.
114
115 In general SSDs will provide more IOPs than spinning disks. This fact and the
116 higher cost may make a xref:pve_ceph_device_classes[class based] separation of
117 pools appealing. Another possibility to speedup OSDs is to use a faster disk
118 as journal or DB/**W**rite-**A**head-**L**og device, see
119 xref:pve_ceph_osds[creating Ceph OSDs]. If a faster disk is used for multiple
120 OSDs, a proper balance between OSD and WAL / DB (or journal) disk must be
121 selected, otherwise the faster disk becomes the bottleneck for all linked OSDs.
122
123 Aside from the disk type, Ceph best performs with an even sized and distributed
124 amount of disks per node. For example, 4 x 500 GB disks with in each node is
125 better than a mixed setup with a single 1 TB and three 250 GB disk.
126
127 One also need to balance OSD count and single OSD capacity. More capacity
128 allows to increase storage density, but it also means that a single OSD
129 failure forces ceph to recover more data at once.
130
131 .Avoid RAID
132 As Ceph handles data object redundancy and multiple parallel writes to disks
133 (OSDs) on its own, using a RAID controller normally doesn’t improve
134 performance or availability. On the contrary, Ceph is designed to handle whole
135 disks on it's own, without any abstraction in between. RAID controller are not
136 designed for the Ceph use case and may complicate things and sometimes even
137 reduce performance, as their write and caching algorithms may interfere with
138 the ones from Ceph.
139
140 WARNING: Avoid RAID controller, use host bus adapter (HBA) instead.
141
142 NOTE: Above recommendations should be seen as a rough guidance for choosing
143 hardware. Therefore, it is still essential to adapt it to your specific needs,
144 test your setup and monitor health and performance continuously.
145
146 [[pve_ceph_install_wizard]]
147 Initial Ceph installation & configuration
148 -----------------------------------------
149
150 [thumbnail="screenshot/gui-node-ceph-install.png"]
151
152 With {pve} you have the benefit of an easy to use installation wizard
153 for Ceph. Click on one of your cluster nodes and navigate to the Ceph
154 section in the menu tree. If Ceph is not already installed you will be
155 offered to do so now.
156
157 The wizard is divided into different sections, where each needs to be
158 finished successfully in order to use Ceph. After starting the installation
159 the wizard will download and install all required packages from {pve}'s ceph
160 repository.
161
162 After finishing the first step, you will need to create a configuration.
163 This step is only needed once per cluster, as this configuration is distributed
164 automatically to all remaining cluster members through {pve}'s clustered
165 xref:chapter_pmxcfs[configuration file system (pmxcfs)].
166
167 The configuration step includes the following settings:
168
169 * *Public Network:* You should setup a dedicated network for Ceph, this
170 setting is required. Separating your Ceph traffic is highly recommended,
171 because it could lead to troubles with other latency dependent services,
172 e.g., cluster communication may decrease Ceph's performance, if not done.
173
174 [thumbnail="screenshot/gui-node-ceph-install-wizard-step2.png"]
175
176 * *Cluster Network:* As an optional step you can go even further and
177 separate the xref:pve_ceph_osds[OSD] replication & heartbeat traffic
178 as well. This will relieve the public network and could lead to
179 significant performance improvements especially in big clusters.
180
181 You have two more options which are considered advanced and therefore
182 should only changed if you are an expert.
183
184 * *Number of replicas*: Defines the how often a object is replicated
185 * *Minimum replicas*: Defines the minimum number of required replicas
186 for I/O to be marked as complete.
187
188 Additionally you need to choose your first monitor node, this is required.
189
190 That's it, you should see a success page as the last step with further
191 instructions on how to go on. You are now prepared to start using Ceph,
192 even though you will need to create additional xref:pve_ceph_monitors[monitors],
193 create some xref:pve_ceph_osds[OSDs] and at least one xref:pve_ceph_pools[pool].
194
195 The rest of this chapter will guide you on how to get the most out of
196 your {pve} based Ceph setup, this will include aforementioned and
197 more like xref:pveceph_fs[CephFS] which is a very handy addition to your
198 new Ceph cluster.
199
200 [[pve_ceph_install]]
201 Installation of Ceph Packages
202 -----------------------------
203 Use {pve} Ceph installation wizard (recommended) or run the following
204 command on each node:
205
206 [source,bash]
207 ----
208 pveceph install
209 ----
210
211 This sets up an `apt` package repository in
212 `/etc/apt/sources.list.d/ceph.list` and installs the required software.
213
214
215 Create initial Ceph configuration
216 ---------------------------------
217
218 [thumbnail="screenshot/gui-ceph-config.png"]
219
220 Use the {pve} Ceph installation wizard (recommended) or run the
221 following command on one node:
222
223 [source,bash]
224 ----
225 pveceph init --network 10.10.10.0/24
226 ----
227
228 This creates an initial configuration at `/etc/pve/ceph.conf` with a
229 dedicated network for ceph. That file is automatically distributed to
230 all {pve} nodes by using xref:chapter_pmxcfs[pmxcfs]. The command also
231 creates a symbolic link from `/etc/ceph/ceph.conf` pointing to that file.
232 So you can simply run Ceph commands without the need to specify a
233 configuration file.
234
235
236 [[pve_ceph_monitors]]
237 Ceph Monitor
238 -----------
239 The Ceph Monitor (MON)
240 footnote:[Ceph Monitor http://docs.ceph.com/docs/luminous/start/intro/]
241 maintains a master copy of the cluster map. For high availability you need to
242 have at least 3 monitors. One monitor will already be installed if you
243 used the installation wizard. You won't need more than 3 monitors as long
244 as your cluster is small to midsize, only really large clusters will
245 need more than that.
246
247
248 Create Monitors
249 ~~~~~~~~~~~~~~~
250
251 [thumbnail="screenshot/gui-ceph-monitor.png"]
252
253 On each node where you want to place a monitor (three monitors are recommended),
254 create it by using the 'Ceph -> Monitor' tab in the GUI or run.
255
256
257 [source,bash]
258 ----
259 pveceph mon create
260 ----
261
262
263 Destroy Monitors
264 ~~~~~~~~~~~~~~~~
265
266 To remove a Ceph Monitor via the GUI first select a node in the tree view and
267 go to the **Ceph -> Monitor** panel. Select the MON and click the **Destroy**
268 button.
269
270 To remove a Ceph Monitor via the CLI first connect to the node on which the MON
271 is running. Then execute the following command:
272 [source,bash]
273 ----
274 pveceph mon destroy
275 ----
276
277 NOTE: At least three Monitors are needed for quorum.
278
279
280 [[pve_ceph_manager]]
281 Ceph Manager
282 ------------
283 The Manager daemon runs alongside the monitors. It provides an interface to
284 monitor the cluster. Since the Ceph luminous release at least one ceph-mgr
285 footnote:[Ceph Manager http://docs.ceph.com/docs/luminous/mgr/] daemon is
286 required.
287
288 Create Manager
289 ~~~~~~~~~~~~~~
290
291 Multiple Managers can be installed, but at any time only one Manager is active.
292
293 [source,bash]
294 ----
295 pveceph mgr create
296 ----
297
298 NOTE: It is recommended to install the Ceph Manager on the monitor nodes. For
299 high availability install more then one manager.
300
301
302 Destroy Manager
303 ~~~~~~~~~~~~~~~
304
305 To remove a Ceph Manager via the GUI first select a node in the tree view and
306 go to the **Ceph -> Monitor** panel. Select the Manager and click the
307 **Destroy** button.
308
309 To remove a Ceph Monitor via the CLI first connect to the node on which the
310 Manager is running. Then execute the following command:
311 [source,bash]
312 ----
313 pveceph mgr destroy
314 ----
315
316 NOTE: A Ceph cluster can function without a Manager, but certain functions like
317 the cluster status or usage require a running Manager.
318
319
320 [[pve_ceph_osds]]
321 Ceph OSDs
322 ---------
323 Ceph **O**bject **S**torage **D**aemons are storing objects for Ceph over the
324 network. It is recommended to use one OSD per physical disk.
325
326 NOTE: By default an object is 4 MiB in size.
327
328 Create OSDs
329 ~~~~~~~~~~~
330
331 [thumbnail="screenshot/gui-ceph-osd-status.png"]
332
333 via GUI or via CLI as follows:
334
335 [source,bash]
336 ----
337 pveceph osd create /dev/sd[X]
338 ----
339
340 TIP: We recommend a Ceph cluster size, starting with 12 OSDs, distributed
341 evenly among your, at least three nodes (4 OSDs on each node).
342
343 If the disk was used before (eg. ZFS/RAID/OSD), to remove partition table, boot
344 sector and any OSD leftover the following command should be sufficient.
345
346 [source,bash]
347 ----
348 ceph-volume lvm zap /dev/sd[X] --destroy
349 ----
350
351 WARNING: The above command will destroy data on the disk!
352
353 .Ceph Bluestore
354
355 Starting with the Ceph Kraken release, a new Ceph OSD storage type was
356 introduced, the so called Bluestore
357 footnote:[Ceph Bluestore http://ceph.com/community/new-luminous-bluestore/].
358 This is the default when creating OSDs since Ceph Luminous.
359
360 [source,bash]
361 ----
362 pveceph osd create /dev/sd[X]
363 ----
364
365 .Block.db and block.wal
366
367 If you want to use a separate DB/WAL device for your OSDs, you can specify it
368 through the '-db_dev' and '-wal_dev' options. The WAL is placed with the DB, if
369 not specified separately.
370
371 [source,bash]
372 ----
373 pveceph osd create /dev/sd[X] -db_dev /dev/sd[Y] -wal_dev /dev/sd[Z]
374 ----
375
376 You can directly choose the size for those with the '-db_size' and '-wal_size'
377 paremeters respectively. If they are not given the following values (in order)
378 will be used:
379
380 * bluestore_block_{db,wal}_size from ceph configuration...
381 ** ... database, section 'osd'
382 ** ... database, section 'global'
383 ** ... file, section 'osd'
384 ** ... file, section 'global'
385 * 10% (DB)/1% (WAL) of OSD size
386
387 NOTE: The DB stores BlueStore’s internal metadata and the WAL is BlueStore’s
388 internal journal or write-ahead log. It is recommended to use a fast SSD or
389 NVRAM for better performance.
390
391
392 .Ceph Filestore
393
394 Before Ceph Luminous, Filestore was used as default storage type for Ceph OSDs.
395 Starting with Ceph Nautilus, {pve} does not support creating such OSDs with
396 'pveceph' anymore. If you still want to create filestore OSDs, use
397 'ceph-volume' directly.
398
399 [source,bash]
400 ----
401 ceph-volume lvm create --filestore --data /dev/sd[X] --journal /dev/sd[Y]
402 ----
403
404 Destroy OSDs
405 ~~~~~~~~~~~~
406
407 To remove an OSD via the GUI first select a {PVE} node in the tree view and go
408 to the **Ceph -> OSD** panel. Select the OSD to destroy. Next click the **OUT**
409 button. Once the OSD status changed from `in` to `out` click the **STOP**
410 button. As soon as the status changed from `up` to `down` select **Destroy**
411 from the `More` drop-down menu.
412
413 To remove an OSD via the CLI run the following commands.
414 [source,bash]
415 ----
416 ceph osd out <ID>
417 systemctl stop ceph-osd@<ID>.service
418 ----
419 NOTE: The first command instructs Ceph not to include the OSD in the data
420 distribution. The second command stops the OSD service. Until this time, no
421 data is lost.
422
423 The following command destroys the OSD. Specify the '-cleanup' option to
424 additionally destroy the partition table.
425 [source,bash]
426 ----
427 pveceph osd destroy <ID>
428 ----
429 WARNING: The above command will destroy data on the disk!
430
431
432 [[pve_ceph_pools]]
433 Ceph Pools
434 ----------
435 A pool is a logical group for storing objects. It holds **P**lacement
436 **G**roups (`PG`, `pg_num`), a collection of objects.
437
438
439 Create Pools
440 ~~~~~~~~~~~~
441
442 [thumbnail="screenshot/gui-ceph-pools.png"]
443
444 When no options are given, we set a default of **128 PGs**, a **size of 3
445 replicas** and a **min_size of 2 replicas** for serving objects in a degraded
446 state.
447
448 NOTE: The default number of PGs works for 2-5 disks. Ceph throws a
449 'HEALTH_WARNING' if you have too few or too many PGs in your cluster.
450
451 It is advised to calculate the PG number depending on your setup, you can find
452 the formula and the PG calculator footnote:[PG calculator
453 http://ceph.com/pgcalc/] online. While PGs can be increased later on, they can
454 never be decreased.
455
456
457 You can create pools through command line or on the GUI on each PVE host under
458 **Ceph -> Pools**.
459
460 [source,bash]
461 ----
462 pveceph pool create <name>
463 ----
464
465 If you would like to automatically also get a storage definition for your pool,
466 mark the checkbox "Add storages" in the GUI or use the command line option
467 '--add_storages' at pool creation.
468
469 Further information on Ceph pool handling can be found in the Ceph pool
470 operation footnote:[Ceph pool operation
471 http://docs.ceph.com/docs/luminous/rados/operations/pools/]
472 manual.
473
474
475 Destroy Pools
476 ~~~~~~~~~~~~~
477
478 To destroy a pool via the GUI select a node in the tree view and go to the
479 **Ceph -> Pools** panel. Select the pool to destroy and click the **Destroy**
480 button. To confirm the destruction of the pool you need to enter the pool name.
481
482 Run the following command to destroy a pool. Specify the '-remove_storages' to
483 also remove the associated storage.
484 [source,bash]
485 ----
486 pveceph pool destroy <name>
487 ----
488
489 NOTE: Deleting the data of a pool is a background task and can take some time.
490 You will notice that the data usage in the cluster is decreasing.
491
492 [[pve_ceph_device_classes]]
493 Ceph CRUSH & device classes
494 ---------------------------
495 The foundation of Ceph is its algorithm, **C**ontrolled **R**eplication
496 **U**nder **S**calable **H**ashing
497 (CRUSH footnote:[CRUSH https://ceph.com/wp-content/uploads/2016/08/weil-crush-sc06.pdf]).
498
499 CRUSH calculates where to store to and retrieve data from, this has the
500 advantage that no central index service is needed. CRUSH works with a map of
501 OSDs, buckets (device locations) and rulesets (data replication) for pools.
502
503 NOTE: Further information can be found in the Ceph documentation, under the
504 section CRUSH map footnote:[CRUSH map http://docs.ceph.com/docs/luminous/rados/operations/crush-map/].
505
506 This map can be altered to reflect different replication hierarchies. The object
507 replicas can be separated (eg. failure domains), while maintaining the desired
508 distribution.
509
510 A common use case is to use different classes of disks for different Ceph pools.
511 For this reason, Ceph introduced the device classes with luminous, to
512 accommodate the need for easy ruleset generation.
513
514 The device classes can be seen in the 'ceph osd tree' output. These classes
515 represent their own root bucket, which can be seen with the below command.
516
517 [source, bash]
518 ----
519 ceph osd crush tree --show-shadow
520 ----
521
522 Example output form the above command:
523
524 [source, bash]
525 ----
526 ID CLASS WEIGHT TYPE NAME
527 -16 nvme 2.18307 root default~nvme
528 -13 nvme 0.72769 host sumi1~nvme
529 12 nvme 0.72769 osd.12
530 -14 nvme 0.72769 host sumi2~nvme
531 13 nvme 0.72769 osd.13
532 -15 nvme 0.72769 host sumi3~nvme
533 14 nvme 0.72769 osd.14
534 -1 7.70544 root default
535 -3 2.56848 host sumi1
536 12 nvme 0.72769 osd.12
537 -5 2.56848 host sumi2
538 13 nvme 0.72769 osd.13
539 -7 2.56848 host sumi3
540 14 nvme 0.72769 osd.14
541 ----
542
543 To let a pool distribute its objects only on a specific device class, you need
544 to create a ruleset with the specific class first.
545
546 [source, bash]
547 ----
548 ceph osd crush rule create-replicated <rule-name> <root> <failure-domain> <class>
549 ----
550
551 [frame="none",grid="none", align="left", cols="30%,70%"]
552 |===
553 |<rule-name>|name of the rule, to connect with a pool (seen in GUI & CLI)
554 |<root>|which crush root it should belong to (default ceph root "default")
555 |<failure-domain>|at which failure-domain the objects should be distributed (usually host)
556 |<class>|what type of OSD backing store to use (eg. nvme, ssd, hdd)
557 |===
558
559 Once the rule is in the CRUSH map, you can tell a pool to use the ruleset.
560
561 [source, bash]
562 ----
563 ceph osd pool set <pool-name> crush_rule <rule-name>
564 ----
565
566 TIP: If the pool already contains objects, all of these have to be moved
567 accordingly. Depending on your setup this may introduce a big performance hit
568 on your cluster. As an alternative, you can create a new pool and move disks
569 separately.
570
571
572 Ceph Client
573 -----------
574
575 [thumbnail="screenshot/gui-ceph-log.png"]
576
577 You can then configure {pve} to use such pools to store VM or
578 Container images. Simply use the GUI too add a new `RBD` storage (see
579 section xref:ceph_rados_block_devices[Ceph RADOS Block Devices (RBD)]).
580
581 You also need to copy the keyring to a predefined location for an external Ceph
582 cluster. If Ceph is installed on the Proxmox nodes itself, then this will be
583 done automatically.
584
585 NOTE: The file name needs to be `<storage_id> + `.keyring` - `<storage_id>` is
586 the expression after 'rbd:' in `/etc/pve/storage.cfg` which is
587 `my-ceph-storage` in the following example:
588
589 [source,bash]
590 ----
591 mkdir /etc/pve/priv/ceph
592 cp /etc/ceph/ceph.client.admin.keyring /etc/pve/priv/ceph/my-ceph-storage.keyring
593 ----
594
595 [[pveceph_fs]]
596 CephFS
597 ------
598
599 Ceph provides also a filesystem running on top of the same object storage as
600 RADOS block devices do. A **M**eta**d**ata **S**erver (`MDS`) is used to map
601 the RADOS backed objects to files and directories, allowing to provide a
602 POSIX-compliant replicated filesystem. This allows one to have a clustered
603 highly available shared filesystem in an easy way if ceph is already used. Its
604 Metadata Servers guarantee that files get balanced out over the whole Ceph
605 cluster, this way even high load will not overload a single host, which can be
606 an issue with traditional shared filesystem approaches, like `NFS`, for
607 example.
608
609 [thumbnail="screenshot/gui-node-ceph-cephfs-panel.png"]
610
611 {pve} supports both, using an existing xref:storage_cephfs[CephFS as storage]
612 to save backups, ISO files or container templates and creating a
613 hyper-converged CephFS itself.
614
615
616 [[pveceph_fs_mds]]
617 Metadata Server (MDS)
618 ~~~~~~~~~~~~~~~~~~~~~
619
620 CephFS needs at least one Metadata Server to be configured and running to be
621 able to work. One can simply create one through the {pve} web GUI's `Node ->
622 CephFS` panel or on the command line with:
623
624 ----
625 pveceph mds create
626 ----
627
628 Multiple metadata servers can be created in a cluster. But with the default
629 settings only one can be active at any time. If an MDS, or its node, becomes
630 unresponsive (or crashes), another `standby` MDS will get promoted to `active`.
631 One can speed up the hand-over between the active and a standby MDS up by using
632 the 'hotstandby' parameter option on create, or if you have already created it
633 you may set/add:
634
635 ----
636 mds standby replay = true
637 ----
638
639 in the ceph.conf respective MDS section. With this enabled, this specific MDS
640 will always poll the active one, so that it can take over faster as it is in a
641 `warm` state. But naturally, the active polling will cause some additional
642 performance impact on your system and active `MDS`.
643
644 .Multiple Active MDS
645
646 Since Luminous (12.2.x) you can also have multiple active metadata servers
647 running, but this is normally only useful for a high count on parallel clients,
648 as else the `MDS` seldom is the bottleneck. If you want to set this up please
649 refer to the ceph documentation. footnote:[Configuring multiple active MDS
650 daemons http://docs.ceph.com/docs/luminous/cephfs/multimds/]
651
652 [[pveceph_fs_create]]
653 Create CephFS
654 ~~~~~~~~~~~~~
655
656 With {pve}'s CephFS integration into you can create a CephFS easily over the
657 Web GUI, the CLI or an external API interface. Some prerequisites are required
658 for this to work:
659
660 .Prerequisites for a successful CephFS setup:
661 - xref:pve_ceph_install[Install Ceph packages], if this was already done some
662 time ago you might want to rerun it on an up to date system to ensure that
663 also all CephFS related packages get installed.
664 - xref:pve_ceph_monitors[Setup Monitors]
665 - xref:pve_ceph_monitors[Setup your OSDs]
666 - xref:pveceph_fs_mds[Setup at least one MDS]
667
668 After this got all checked and done you can simply create a CephFS through
669 either the Web GUI's `Node -> CephFS` panel or the command line tool `pveceph`,
670 for example with:
671
672 ----
673 pveceph fs create --pg_num 128 --add-storage
674 ----
675
676 This creates a CephFS named `'cephfs'' using a pool for its data named
677 `'cephfs_data'' with `128` placement groups and a pool for its metadata named
678 `'cephfs_metadata'' with one quarter of the data pools placement groups (`32`).
679 Check the xref:pve_ceph_pools[{pve} managed Ceph pool chapter] or visit the
680 Ceph documentation for more information regarding a fitting placement group
681 number (`pg_num`) for your setup footnote:[Ceph Placement Groups
682 http://docs.ceph.com/docs/luminous/rados/operations/placement-groups/].
683 Additionally, the `'--add-storage'' parameter will add the CephFS to the {pve}
684 storage configuration after it was created successfully.
685
686 Destroy CephFS
687 ~~~~~~~~~~~~~~
688
689 WARNING: Destroying a CephFS will render all its data unusable, this cannot be
690 undone!
691
692 If you really want to destroy an existing CephFS you first need to stop, or
693 destroy, all metadata servers (`M̀DS`). You can destroy them either over the Web
694 GUI or the command line interface, with:
695
696 ----
697 pveceph mds destroy NAME
698 ----
699 on each {pve} node hosting a MDS daemon.
700
701 Then, you can remove (destroy) CephFS by issuing a:
702
703 ----
704 ceph fs rm NAME --yes-i-really-mean-it
705 ----
706 on a single node hosting Ceph. After this you may want to remove the created
707 data and metadata pools, this can be done either over the Web GUI or the CLI
708 with:
709
710 ----
711 pveceph pool destroy NAME
712 ----
713
714
715 Ceph monitoring and troubleshooting
716 -----------------------------------
717 A good start is to continuosly monitor the ceph health from the start of
718 initial deployment. Either through the ceph tools itself, but also by accessing
719 the status through the {pve} link:api-viewer/index.html[API].
720
721 The following ceph commands below can be used to see if the cluster is healthy
722 ('HEALTH_OK'), if there are warnings ('HEALTH_WARN'), or even errors
723 ('HEALTH_ERR'). If the cluster is in an unhealthy state the status commands
724 below will also give you an overview of the current events and actions to take.
725
726 ----
727 # single time output
728 pve# ceph -s
729 # continuously output status changes (press CTRL+C to stop)
730 pve# ceph -w
731 ----
732
733 To get a more detailed view, every ceph service has a log file under
734 `/var/log/ceph/` and if there is not enough detail, the log level can be
735 adjusted footnote:[Ceph log and debugging http://docs.ceph.com/docs/luminous/rados/troubleshooting/log-and-debug/].
736
737 You can find more information about troubleshooting
738 footnote:[Ceph troubleshooting http://docs.ceph.com/docs/luminous/rados/troubleshooting/]
739 a Ceph cluster on the official website.
740
741
742 ifdef::manvolnum[]
743 include::pve-copyright.adoc[]
744 endif::manvolnum[]