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
41 the Storage documentation on how to add a storage. A backup storage
42 must be a file level storage, as backups are stored as regular files.
43 In most situations, using a NFS server is a good way to store backups.
44 You can save those backups later to a tape drive, for off-site
49 Backup jobs can be scheduled so that they are executed automatically
50 on specific days and times, for selectable nodes and guest systems.
51 Configuration of scheduled backups is done at the Datacenter level in
52 the GUI, which will generate a cron entry in /etc/cron.d/vzdump.
57 There are several ways to provide consistency (option `mode`),
58 depending on the guest type.
60 .Backup modes for VMs:
64 This mode provides the highest consistency of the backup, at the cost
65 of a short downtime in the VM operation. It works by executing an
66 orderly shutdown of the VM, and then runs a background Qemu process to
67 backup the VM data. After the backup is started, the VM goes to full
68 operation mode if it was previously running. Consistency is guaranteed
69 by using the live backup feature.
73 This mode is provided for compatibility reason, and suspends the VM
74 before calling the `snapshot` mode. Since suspending the VM results in
75 a longer downtime and does not necessarily improve the data
76 consistency, the use of the `snapshot` mode is recommended instead.
80 This mode provides the lowest operation downtime, at the cost of a
81 small inconsistency risk. It works by performing a {pve} live
82 backup, in which data blocks are copied while the VM is running. If the
83 guest agent is enabled (`agent: 1`) and running, it calls
84 `guest-fsfreeze-freeze` and `guest-fsfreeze-thaw` to improve
87 A technical overview of the {pve} live backup for QemuServer can
89 https://git.proxmox.com/?p=pve-qemu.git;a=blob_plain;f=backup.txt[here].
91 NOTE: {pve} live backup provides snapshot-like semantics on any
92 storage type. It does not require that the underlying storage supports
93 snapshots. Also please note that since the backups are done via
94 a background Qemu process, a stopped VM will appear as running for a
95 short amount of time while the VM disks are being read by Qemu.
96 However the VM itself is not booted, only its disk(s) are read.
98 .Backup modes for Containers:
102 Stop the container for the duration of the backup. This potentially
103 results in a very long downtime.
107 This mode uses rsync to copy the container data to a temporary
108 location (see option `--tmpdir`). Then the container is suspended and
109 a second rsync copies changed files. After that, the container is
110 started (resumed) again. This results in minimal downtime, but needs
111 additional space to hold the container copy.
113 When the container is on a local file system and the target storage of
114 the backup is an NFS/CIFS server, you should set `--tmpdir` to reside on a
115 local file system too, as this will result in a many fold performance
116 improvement. Use of a local `tmpdir` is also required if you want to
117 backup a local container using ACLs in suspend mode if the backup
118 storage is an NFS server.
122 This mode uses the snapshotting facilities of the underlying
123 storage. First, the container will be suspended to ensure data consistency.
124 A temporary snapshot of the container's volumes will be made and the
125 snapshot content will be archived in a tar file. Finally, the temporary
126 snapshot is deleted again.
128 NOTE: `snapshot` mode requires that all backed up volumes are on a storage that
129 supports snapshots. Using the `backup=no` mount point option individual volumes
130 can be excluded from the backup (and thus this requirement).
132 // see PVE::VZDump::LXC::prepare()
133 NOTE: By default additional mount points besides the Root Disk mount point are
134 not included in backups. For volume mount points you can set the *Backup* option
135 to include the mount point in the backup. Device and bind mounts are never
136 backed up as their content is managed outside the {pve} storage library.
141 Newer versions of vzdump encode the guest type and the
142 backup time into the filename, for example
144 vzdump-lxc-105-2009_10_09-11_04_43.tar
146 That way it is possible to store several backup in the same directory. You can
147 limit the number of backups that are kept with various retention options, see
148 the xref:vzdump_retention[Backup Retention] section below.
150 Backup File Compression
151 -----------------------
153 The backup file can be compressed with one of the following algorithms: `lzo`
154 footnote:[Lempel–Ziv–Oberhumer a lossless data compression algorithm
155 https://en.wikipedia.org/wiki/Lempel-Ziv-Oberhumer], `gzip` footnote:[gzip -
156 based on the DEFLATE algorithm https://en.wikipedia.org/wiki/Gzip] or `zstd`
157 footnote:[Zstandard a lossless data compression algorithm
158 https://en.wikipedia.org/wiki/Zstandard].
160 Currently, Zstandard (zstd) is the fastest of these three algorithms.
161 Multi-threading is another advantage of zstd over lzo and gzip. Lzo and gzip
162 are more widely used and often installed by default.
164 You can install pigz footnote:[pigz - parallel implementation of gzip
165 https://zlib.net/pigz/] as a drop-in replacement for gzip to provide better
166 performance due to multi-threading. For pigz & zstd, the amount of
167 threads/cores can be adjusted. See the
168 xref:vzdump_configuration[configuration options] below.
170 The extension of the backup file name can usually be used to determine which
171 compression algorithm has been used to create the backup.
174 |.zst | Zstandard (zstd) compression
175 |.gz or .tgz | gzip compression
176 |.lzo | lzo compression
179 If the backup file name doesn't end with one of the above file extensions, then
180 it was not compressed by vzdump.
185 For Proxmox Backup Server storages, you can optionally set up client-side
186 encryption of backups, see xref:storage_pbs_encryption[the corresponding section.]
192 With the `prune-backups` option you can specify which backups you want to keep
193 in a flexible manner. The following retention options are available:
195 `keep-all <boolean>` ::
196 Keep all backups. If this is `true`, no other options can be set.
199 Keep the last `<N>` backups.
202 Keep backups for the last `<N>` hours. If there is more than one
203 backup for a single hour, only the latest is kept.
206 Keep backups for the last `<N>` days. If there is more than one
207 backup for a single day, only the latest is kept.
210 Keep backups for the last `<N>` weeks. If there is more than one
211 backup for a single week, only the latest is kept.
213 NOTE: Weeks start on Monday and end on Sunday. The software uses the
214 `ISO week date`-system and handles weeks at the end of the year correctly.
216 `keep-monthly <N>` ::
217 Keep backups for the last `<N>` months. If there is more than one
218 backup for a single month, only the latest is kept.
221 Keep backups for the last `<N>` years. If there is more than one
222 backup for a single year, only the latest is kept.
224 The retention options are processed in the order given above. Each option
225 only covers backups within its time period. The next option does not take care
226 of already covered backups. It will only consider older backups.
228 Specify the retention options you want to use as a
229 comma-separated list, for example:
231 # vzdump 777 --prune-backups keep-last=3,keep-daily=13,keep-yearly=9
233 While you can pass `prune-backups` directly to `vzdump`, it is often more
234 sensible to configure the setting on the storage level, which can be done via
237 NOTE: The old `maxfiles` option is deprecated and should be replaced either by
238 `keep-last` or, in case `maxfiles` was `0` for unlimited retention, by
245 You can use the https://pbs.proxmox.com/docs/prune-simulator[prune simulator
246 of the Proxmox Backup Server documentation] to explore the effect of different
247 retention options with various backup schedules.
249 Retention Settings Example
250 ~~~~~~~~~~~~~~~~~~~~~~~~~~
252 The backup frequency and retention of old backups may depend on how often data
253 changes, and how important an older state may be, in a specific work load.
254 When backups act as a company's document archive, there may also be legal
255 requirements for how long backups must be kept.
257 For this example, we assume that you are doing daily backups, have a retention
258 period of 10 years, and the period between backups stored gradually grows.
260 `keep-last=3` - even if only daily backups are taken, an admin may want to
261 create an extra one just before or after a big upgrade. Setting keep-last
264 `keep-hourly` is not set - for daily backups this is not relevant. You cover
265 extra manual backups already, with keep-last.
267 `keep-daily=13` - together with keep-last, which covers at least one
268 day, this ensures that you have at least two weeks of backups.
270 `keep-weekly=8` - ensures that you have at least two full months of
273 `keep-monthly=11` - together with the previous keep settings, this
274 ensures that you have at least a year of monthly backups.
276 `keep-yearly=9` - this is for the long term archive. As you covered the
277 current year with the previous options, you would set this to nine for the
278 remaining ones, giving you a total of at least 10 years of coverage.
280 We recommend that you use a higher retention period than is minimally required
281 by your environment; you can always reduce it if you find it is unnecessarily
282 high, but you cannot recreate backups once they have been removed.
288 A backup archive can be restored through the {pve} web GUI or through the
292 `pct restore`:: Container restore utility
294 `qmrestore`:: Virtual Machine restore utility
296 For details see the corresponding manual pages.
301 Restoring one or more big backups may need a lot of resources, especially
302 storage bandwidth for both reading from the backup storage and writing to
303 the target storage. This can negatively affect other virtual guests as access
304 to storage can get congested.
306 To avoid this you can set bandwidth limits for a backup job. {pve}
307 implements two kinds of limits for restoring and archive:
309 * per-restore limit: denotes the maximal amount of bandwidth for
310 reading from a backup archive
312 * per-storage write limit: denotes the maximal amount of bandwidth used for
313 writing to a specific storage
315 The read limit indirectly affects the write limit, as we cannot write more
316 than we read. A smaller per-job limit will overwrite a bigger per-storage
317 limit. A bigger per-job limit will only overwrite the per-storage limit if
318 you have `Data.Allocate' permissions on the affected storage.
320 You can use the `--bwlimit <integer>` option from the restore CLI commands
321 to set up a restore job specific bandwidth limit. Kibit/s is used as unit
322 for the limit, this means passing `10240' will limit the read speed of the
323 backup to 10 MiB/s, ensuring that the rest of the possible storage bandwidth
324 is available for the already running virtual guests, and thus the backup
325 does not impact their operations.
327 NOTE: You can use `0` for the `bwlimit` parameter to disable all limits for
328 a specific restore job. This can be helpful if you need to restore a very
329 important virtual guest as fast as possible. (Needs `Data.Allocate'
330 permissions on storage)
332 Most times your storage's generally available bandwidth stays the same over
333 time, thus we implemented the possibility to set a default bandwidth limit
334 per configured storage, this can be done with:
337 # pvesm set STORAGEID --bwlimit restore=KIBs
340 [[vzdump_configuration]]
344 Global configuration is stored in `/etc/vzdump.conf`. The file uses a
345 simple colon separated key/value format. Each line has the following
350 Blank lines in the file are ignored, and lines starting with a `#`
351 character are treated as comments and are also ignored. Values from
352 this file are used as default, and can be overwritten on the command
355 We currently support the following options:
357 include::vzdump.conf.5-opts.adoc[]
360 .Example `vzdump.conf` Configuration
362 tmpdir: /mnt/fast_local_disk
363 storage: my_backup_storage
371 You can specify a hook script with option `--script`. This script is
372 called at various phases of the backup process, with parameters
373 accordingly set. You can find an example in the documentation
374 directory (`vzdump-hook-script.pl`).
379 NOTE: this option is only available for container backups.
381 `vzdump` skips the following files by default (disable with the option
388 You can also manually specify (additional) exclude paths, for example:
390 # vzdump 777 --exclude-path /tmp/ --exclude-path '/var/foo*'
392 excludes the directory `/tmp/` and any file or directory named `/var/foo`,
393 `/var/foobar`, and so on.
395 Paths that do not start with a `/` are not anchored to the container's root,
396 but will match relative to any subdirectory. For example:
398 # vzdump 777 --exclude-path bar
400 excludes any file or directoy named `/bar`, `/var/bar`, `/var/foo/bar`, and
401 so on, but not `/bar2`.
403 Configuration files are also stored inside the backup archive
404 (in `./etc/vzdump/`) and will be correctly restored.
409 Simply dump guest 777 - no snapshot, just archive the guest private area and
410 configuration files to the default dump directory (usually
411 `/var/lib/vz/dump/`).
415 Use rsync and suspend/resume to create a snapshot (minimal downtime).
417 # vzdump 777 --mode suspend
419 Backup all guest systems and send notification mails to root and admin.
421 # vzdump --all --mode suspend --mailto root --mailto admin
423 Use snapshot mode (no downtime) and non-default dump directory.
425 # vzdump 777 --dumpdir /mnt/backup --mode snapshot
427 Backup more than one guest (selectively)
429 # vzdump 101 102 103 --mailto root
431 Backup all guests excluding 101 and 102
433 # vzdump --mode suspend --exclude 101,102
435 Restore a container to a new CT 600
437 # pct restore 600 /mnt/backup/vzdump-lxc-777.tar
439 Restore a QemuServer VM to VM 601
441 # qmrestore /mnt/backup/vzdump-qemu-888.vma 601
443 Clone an existing container 101 to a new container 300 with a 4GB root
444 file system, using pipes
446 # vzdump 101 --stdout | pct restore --rootfs 4 300 -
450 include::pve-copyright.adoc[]