10 vzdump - Backup Utility for VMs and Containers
16 include::vzdump.1-synopsis.adoc[]
28 Backups are a requirement for any sensible IT deployment, and {pve}
29 provides a fully integrated solution, using the capabilities of each
30 storage and each guest system type. This allows the system
31 administrator to fine tune via the `mode` option between consistency
32 of the backups and downtime of the guest system.
34 {pve} backups are always full backups - containing the VM/CT
35 configuration and all data. Backups can be started via the GUI or via
36 the `vzdump` command-line tool.
40 Before a backup can run, a backup storage must be defined. Refer to the
41 xref:chapter_storage[storage documentation] on how to add a storage. It can
42 either be a Proxmox Backup Server storage, where backups are stored as
43 de-duplicated chunks and metadata, or a file-level storage, where backups are
44 stored as regular files. Using Proxmox Backup Server on a dedicated host is
45 recommended, because of its advanced features. Using an NFS server is a good
46 alternative. In both cases, you might want to save those backups later to a tape
47 drive, for off-site archiving.
51 Backup jobs can be scheduled so that they are executed automatically on specific
52 days and times, for selectable nodes and guest systems. See the
53 xref:vzdump_jobs[Backup Jobs] section for more.
58 There are several ways to provide consistency (option `mode`),
59 depending on the guest type.
61 .Backup modes for VMs:
65 This mode provides the highest consistency of the backup, at the cost
66 of a short downtime in the VM operation. It works by executing an
67 orderly shutdown of the VM, and then runs a background QEMU process to
68 backup the VM data. After the backup is started, the VM goes to full
69 operation mode if it was previously running. Consistency is guaranteed
70 by using the live backup feature.
74 This mode is provided for compatibility reason, and suspends the VM
75 before calling the `snapshot` mode. Since suspending the VM results in
76 a longer downtime and does not necessarily improve the data
77 consistency, the use of the `snapshot` mode is recommended instead.
81 This mode provides the lowest operation downtime, at the cost of a
82 small inconsistency risk. It works by performing a {pve} live
83 backup, in which data blocks are copied while the VM is running. If the
84 guest agent is enabled (`agent: 1`) and running, it calls
85 `guest-fsfreeze-freeze` and `guest-fsfreeze-thaw` to improve
88 A technical overview of the {pve} live backup for QemuServer can
90 https://git.proxmox.com/?p=pve-qemu.git;a=blob_plain;f=backup.txt[here].
92 NOTE: {pve} live backup provides snapshot-like semantics on any
93 storage type. It does not require that the underlying storage supports
94 snapshots. Also please note that since the backups are done via
95 a background QEMU process, a stopped VM will appear as running for a
96 short amount of time while the VM disks are being read by QEMU.
97 However the VM itself is not booted, only its disk(s) are read.
99 .Backup modes for Containers:
103 Stop the container for the duration of the backup. This potentially
104 results in a very long downtime.
108 This mode uses rsync to copy the container data to a temporary
109 location (see option `--tmpdir`). Then the container is suspended and
110 a second rsync copies changed files. After that, the container is
111 started (resumed) again. This results in minimal downtime, but needs
112 additional space to hold the container copy.
114 When the container is on a local file system and the target storage of
115 the backup is an NFS/CIFS server, you should set `--tmpdir` to reside on a
116 local file system too, as this will result in a many fold performance
117 improvement. Use of a local `tmpdir` is also required if you want to
118 backup a local container using ACLs in suspend mode if the backup
119 storage is an NFS server.
123 This mode uses the snapshotting facilities of the underlying
124 storage. First, the container will be suspended to ensure data consistency.
125 A temporary snapshot of the container's volumes will be made and the
126 snapshot content will be archived in a tar file. Finally, the temporary
127 snapshot is deleted again.
129 NOTE: `snapshot` mode requires that all backed up volumes are on a storage that
130 supports snapshots. Using the `backup=no` mount point option individual volumes
131 can be excluded from the backup (and thus this requirement).
133 // see PVE::VZDump::LXC::prepare()
134 NOTE: By default additional mount points besides the Root Disk mount point are
135 not included in backups. For volume mount points you can set the *Backup* option
136 to include the mount point in the backup. Device and bind mounts are never
137 backed up as their content is managed outside the {pve} storage library.
142 Newer versions of vzdump encode the guest type and the
143 backup time into the filename, for example
145 vzdump-lxc-105-2009_10_09-11_04_43.tar
147 That way it is possible to store several backup in the same directory. You can
148 limit the number of backups that are kept with various retention options, see
149 the xref:vzdump_retention[Backup Retention] section below.
151 Backup File Compression
152 -----------------------
154 The backup file can be compressed with one of the following algorithms: `lzo`
155 footnote:[Lempel–Ziv–Oberhumer a lossless data compression algorithm
156 https://en.wikipedia.org/wiki/Lempel-Ziv-Oberhumer], `gzip` footnote:[gzip -
157 based on the DEFLATE algorithm https://en.wikipedia.org/wiki/Gzip] or `zstd`
158 footnote:[Zstandard a lossless data compression algorithm
159 https://en.wikipedia.org/wiki/Zstandard].
161 Currently, Zstandard (zstd) is the fastest of these three algorithms.
162 Multi-threading is another advantage of zstd over lzo and gzip. Lzo and gzip
163 are more widely used and often installed by default.
165 You can install pigz footnote:[pigz - parallel implementation of gzip
166 https://zlib.net/pigz/] as a drop-in replacement for gzip to provide better
167 performance due to multi-threading. For pigz & zstd, the amount of
168 threads/cores can be adjusted. See the
169 xref:vzdump_configuration[configuration options] below.
171 The extension of the backup file name can usually be used to determine which
172 compression algorithm has been used to create the backup.
175 |.zst | Zstandard (zstd) compression
176 |.gz or .tgz | gzip compression
177 |.lzo | lzo compression
180 If the backup file name doesn't end with one of the above file extensions, then
181 it was not compressed by vzdump.
186 For Proxmox Backup Server storages, you can optionally set up client-side
187 encryption of backups, see xref:storage_pbs_encryption[the corresponding section.]
193 Besides triggering a backup manually, you can also setup periodic jobs that
194 backup all, or a selection of virtual guest to a storage. You can manage the
195 jobs in the UI under 'Datacenter' -> 'Backup' or via the `/cluster/backup` API
196 endpoint. Both will generate job entries in `/etc/pve/jobs.cfg`, which are
197 parsed and executed by the `pvescheduler` daemon.
199 A job is either configured for all cluster nodes or a specific node, and is
200 executed according to a given schedule. The format for the schedule is very
201 similar to `systemd` calendar events, see the
202 xref:chapter_calendar_events[calendar events] section for details. The
203 'Schedule' field in the UI can be freely edited, and it contains several
204 examples that can be used as a starting point in its drop-down list.
206 You can configure job-specific xref:vzdump_retention[retention options]
207 overriding those from the storage or node configuration, as well as a
208 xref:vzdump_notes[template for notes] for additional information to be saved
209 together with the backup.
211 Since scheduled backups miss their execution when the host was offline or the
212 pvescheduler was disabled during the scheduled time, it is possible to configure
213 the behaviour for catching up. By enabling the `Repeat missed` option
214 (`repeat-missed` in the config), you can tell the scheduler that it should run
215 missed jobs as soon as possible.
217 There are a few settings for tuning backup performance not exposed in the UI.
218 The most notable is `bwlimit` for limiting IO bandwidth. The amount of threads
219 used for the compressor can be controlled with the `pigz` (replacing `gzip`),
220 respectively, `zstd` setting. Furthermore, there are `ionice` and, as part of
221 the `performance` setting, `max-workers` (affects VM backups only) and
222 `pbs-entries-max` (affects container backups only). See the
223 xref:vzdump_configuration[configuration options] for details.
229 With the `prune-backups` option you can specify which backups you want to keep
230 in a flexible manner. The following retention options are available:
232 `keep-all <boolean>` ::
233 Keep all backups. If this is `true`, no other options can be set.
236 Keep the last `<N>` backups.
239 Keep backups for the last `<N>` hours. If there is more than one
240 backup for a single hour, only the latest is kept.
243 Keep backups for the last `<N>` days. If there is more than one
244 backup for a single day, only the latest is kept.
247 Keep backups for the last `<N>` weeks. If there is more than one
248 backup for a single week, only the latest is kept.
250 NOTE: Weeks start on Monday and end on Sunday. The software uses the
251 `ISO week date`-system and handles weeks at the end of the year correctly.
253 `keep-monthly <N>` ::
254 Keep backups for the last `<N>` months. If there is more than one
255 backup for a single month, only the latest is kept.
258 Keep backups for the last `<N>` years. If there is more than one
259 backup for a single year, only the latest is kept.
261 The retention options are processed in the order given above. Each option
262 only covers backups within its time period. The next option does not take care
263 of already covered backups. It will only consider older backups.
265 Specify the retention options you want to use as a
266 comma-separated list, for example:
268 # vzdump 777 --prune-backups keep-last=3,keep-daily=13,keep-yearly=9
270 While you can pass `prune-backups` directly to `vzdump`, it is often more
271 sensible to configure the setting on the storage level, which can be done via
274 NOTE: The old `maxfiles` option is deprecated and should be replaced either by
275 `keep-last` or, in case `maxfiles` was `0` for unlimited retention, by
282 You can use the https://pbs.proxmox.com/docs/prune-simulator[prune simulator
283 of the Proxmox Backup Server documentation] to explore the effect of different
284 retention options with various backup schedules.
286 Retention Settings Example
287 ~~~~~~~~~~~~~~~~~~~~~~~~~~
289 The backup frequency and retention of old backups may depend on how often data
290 changes, and how important an older state may be, in a specific work load.
291 When backups act as a company's document archive, there may also be legal
292 requirements for how long backups must be kept.
294 For this example, we assume that you are doing daily backups, have a retention
295 period of 10 years, and the period between backups stored gradually grows.
297 `keep-last=3` - even if only daily backups are taken, an admin may want to
298 create an extra one just before or after a big upgrade. Setting keep-last
301 `keep-hourly` is not set - for daily backups this is not relevant. You cover
302 extra manual backups already, with keep-last.
304 `keep-daily=13` - together with keep-last, which covers at least one
305 day, this ensures that you have at least two weeks of backups.
307 `keep-weekly=8` - ensures that you have at least two full months of
310 `keep-monthly=11` - together with the previous keep settings, this
311 ensures that you have at least a year of monthly backups.
313 `keep-yearly=9` - this is for the long term archive. As you covered the
314 current year with the previous options, you would set this to nine for the
315 remaining ones, giving you a total of at least 10 years of coverage.
317 We recommend that you use a higher retention period than is minimally required
318 by your environment; you can always reduce it if you find it is unnecessarily
319 high, but you cannot recreate backups once they have been removed.
321 [[vzdump_protection]]
325 You can mark a backup as `protected` to prevent its removal. Attempting to
326 remove a protected backup via {pve}'s UI, CLI or API will fail. However, this
327 is enforced by {pve} and not the file-system, that means that a manual removal
328 of a backup file itself is still possible for anyone with write access to the
329 underlying backup storage.
331 NOTE: Protected backups are ignored by pruning and do not count towards the
334 For filesystem-based storages, the protection is implemented via a sentinel file
335 `<backup-name>.protected`. For Proxmox Backup Server, it is handled on the
336 server side (available since Proxmox Backup Server version 2.1).
338 Use the storage option `max-protected-backups` to control how many protected
339 backups per guest are allowed on the storage. Use `-1` for unlimited. The
340 default is unlimited for users with `Datastore.Allocate` privilege and `5` for
347 You can add notes to backups using the 'Edit Notes' button in the UI or via the
350 It is also possible to specify a template for generating notes dynamically for
351 a backup job and for manual backup. The template string can contain variables,
352 surrounded by two curly braces, which will be replaced by the corresponding
353 value when the backup is executed.
355 Currently supported are:
357 * `{{cluster}}` the cluster name, if any
358 * `{{guestname}}` the virtual guest's assigned name
359 * `{{node}}` the host name of the node the backup is being created
360 * `{{vmid}}` the numerical VMID of the guest
362 When specified via API or CLI, it needs to be a single line, where newline and
363 backslash need to be escaped as literal `\n` and `\\` respectively.
369 A backup archive can be restored through the {pve} web GUI or through the
373 `pct restore`:: Container restore utility
375 `qmrestore`:: Virtual Machine restore utility
377 For details see the corresponding manual pages.
382 Restoring one or more big backups may need a lot of resources, especially
383 storage bandwidth for both reading from the backup storage and writing to
384 the target storage. This can negatively affect other virtual guests as access
385 to storage can get congested.
387 To avoid this you can set bandwidth limits for a backup job. {pve}
388 implements two kinds of limits for restoring and archive:
390 * per-restore limit: denotes the maximal amount of bandwidth for
391 reading from a backup archive
393 * per-storage write limit: denotes the maximal amount of bandwidth used for
394 writing to a specific storage
396 The read limit indirectly affects the write limit, as we cannot write more
397 than we read. A smaller per-job limit will overwrite a bigger per-storage
398 limit. A bigger per-job limit will only overwrite the per-storage limit if
399 you have `Data.Allocate' permissions on the affected storage.
401 You can use the `--bwlimit <integer>` option from the restore CLI commands
402 to set up a restore job specific bandwidth limit. KiB/s is used as unit
403 for the limit, this means passing `10240' will limit the read speed of the
404 backup to 10 MiB/s, ensuring that the rest of the possible storage bandwidth
405 is available for the already running virtual guests, and thus the backup
406 does not impact their operations.
408 NOTE: You can use `0` for the `bwlimit` parameter to disable all limits for
409 a specific restore job. This can be helpful if you need to restore a very
410 important virtual guest as fast as possible. (Needs `Data.Allocate'
411 permissions on storage)
413 Most times your storage's generally available bandwidth stays the same over
414 time, thus we implemented the possibility to set a default bandwidth limit
415 per configured storage, this can be done with:
418 # pvesm set STORAGEID --bwlimit restore=KIBs
424 Restoring a large backup can take a long time, in which a guest is still
425 unavailable. For VM backups stored on a Proxmox Backup Server, this wait
426 time can be mitigated using the live-restore option.
428 Enabling live-restore via either the checkbox in the GUI or the `--live-restore`
429 argument of `qmrestore` causes the VM to start as soon as the restore
430 begins. Data is copied in the background, prioritizing chunks that the VM is
433 Note that this comes with two caveats:
435 * During live-restore, the VM will operate with limited disk read speeds, as
436 data has to be loaded from the backup server (once loaded, it is immediately
437 available on the destination storage however, so accessing data twice only
438 incurs the penalty the first time). Write speeds are largely unaffected.
439 * If the live-restore fails for any reason, the VM will be left in an
440 undefined state - that is, not all data might have been copied from the
441 backup, and it is _most likely_ not possible to keep any data that was written
442 during the failed restore operation.
444 This mode of operation is especially useful for large VMs, where only a small
445 amount of data is required for initial operation, e.g. web servers - once the OS
446 and necessary services have been started, the VM is operational, while the
447 background task continues copying seldom used data.
452 The 'File Restore' button in the 'Backups' tab of the storage GUI can be used to
453 open a file browser directly on the data contained in a backup. This feature
454 is only available for backups on a Proxmox Backup Server.
456 For containers, the first layer of the file tree shows all included 'pxar'
457 archives, which can be opened and browsed freely. For VMs, the first layer shows
458 contained drive images, which can be opened to reveal a list of supported
459 storage technologies found on the drive. In the most basic case, this will be an
460 entry called 'part', representing a partition table, which contains entries for
461 each partition found on the drive. Note that for VMs, not all data might be
462 accessible (unsupported guest file systems, storage technologies, etc...).
464 Files and directories can be downloaded using the 'Download' button, the latter
465 being compressed into a zip archive on the fly.
467 To enable secure access to VM images, which might contain untrusted data, a
468 temporary VM (not visible as a guest) is started. This does not mean that data
469 downloaded from such an archive is inherently safe, but it avoids exposing the
470 hypervisor system to danger. The VM will stop itself after a timeout. This
471 entire process happens transparently from a user's point of view.
473 NOTE: For troubleshooting purposes, each temporary VM instance generates a log
474 file in `/var/log/proxmox-backup/file-restore/`. The log file might contain
475 additional information in case an attempt to restore individual files or
476 accessing file systems contained in a backup archive fails.
478 [[vzdump_configuration]]
482 Global configuration is stored in `/etc/vzdump.conf`. The file uses a
483 simple colon separated key/value format. Each line has the following
488 Blank lines in the file are ignored, and lines starting with a `#`
489 character are treated as comments and are also ignored. Values from
490 this file are used as default, and can be overwritten on the command
493 We currently support the following options:
495 include::vzdump.conf.5-opts.adoc[]
498 .Example `vzdump.conf` Configuration
500 tmpdir: /mnt/fast_local_disk
501 storage: my_backup_storage
509 You can specify a hook script with option `--script`. This script is
510 called at various phases of the backup process, with parameters
511 accordingly set. You can find an example in the documentation
512 directory (`vzdump-hook-script.pl`).
517 NOTE: this option is only available for container backups.
519 `vzdump` skips the following files by default (disable with the option
526 You can also manually specify (additional) exclude paths, for example:
528 # vzdump 777 --exclude-path /tmp/ --exclude-path '/var/foo*'
530 excludes the directory `/tmp/` and any file or directory named `/var/foo`,
531 `/var/foobar`, and so on.
533 Paths that do not start with a `/` are not anchored to the container's root,
534 but will match relative to any subdirectory. For example:
536 # vzdump 777 --exclude-path bar
538 excludes any file or directory named `/bar`, `/var/bar`, `/var/foo/bar`, and
539 so on, but not `/bar2`.
541 Configuration files are also stored inside the backup archive
542 (in `./etc/vzdump/`) and will be correctly restored.
547 Simply dump guest 777 - no snapshot, just archive the guest private area and
548 configuration files to the default dump directory (usually
549 `/var/lib/vz/dump/`).
553 Use rsync and suspend/resume to create a snapshot (minimal downtime).
555 # vzdump 777 --mode suspend
557 Backup all guest systems and send notification mails to root and admin.
558 Due to `mailto` being set and `notification-mode` being set to `auto` by
559 default, the notification mails are sent via the system's `sendmail`
560 command instead of the notification system.
562 # vzdump --all --mode suspend --mailto root --mailto admin
564 Use snapshot mode (no downtime) and non-default dump directory.
566 # vzdump 777 --dumpdir /mnt/backup --mode snapshot
568 Backup more than one guest (selectively)
570 # vzdump 101 102 103 --mailto root
572 Backup all guests excluding 101 and 102
574 # vzdump --mode suspend --exclude 101,102
576 Restore a container to a new CT 600
578 # pct restore 600 /mnt/backup/vzdump-lxc-777.tar
580 Restore a QemuServer VM to VM 601
582 # qmrestore /mnt/backup/vzdump-qemu-888.vma 601
584 Clone an existing container 101 to a new container 300 with a 4GB root
585 file system, using pipes
587 # vzdump 101 --stdout | pct restore --rootfs 4 300 -
591 include::pve-copyright.adoc[]