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  1. [[chapter_vzdump]]
  2. ifdef::manvolnum[]
  3. vzdump(1)
  4. =========
  5. :pve-toplevel:
  6. NAME
  7. ----
  8. vzdump - Backup Utility for VMs and Containers
  10. --------
  11. include::vzdump.1-synopsis.adoc[]
  13. -----------
  14. endif::manvolnum[]
  15. ifndef::manvolnum[]
  16. Backup and Restore
  17. ==================
  18. :pve-toplevel:
  19. endif::manvolnum[]
  20. Backups are a requirement for any sensible IT deployment, and {pve}
  21. provides a fully integrated solution, using the capabilities of each
  22. storage and each guest system type. This allows the system
  23. administrator to fine tune via the `mode` option between consistency
  24. of the backups and downtime of the guest system.
  25. {pve} backups are always full backups - containing the VM/CT
  26. configuration and all data. Backups can be started via the GUI or via
  27. the `vzdump` command line tool.
  28. .Backup Storage
  29. Before a backup can run, a backup storage must be defined. Refer to
  30. the Storage documentation on how to add a storage. A backup storage
  31. must be a file level storage, as backups are stored as regular files.
  32. In most situations, using a NFS server is a good way to store backups.
  33. You can save those backups later to a tape drive, for off-site
  34. archiving.
  35. .Scheduled Backup
  36. Backup jobs can be scheduled so that they are executed automatically
  37. on specific days and times, for selectable nodes and guest systems.
  38. Configuration of scheduled backups is done at the Datacenter level in
  39. the GUI, which will generate a cron entry in /etc/cron.d/vzdump.
  40. Backup modes
  41. ------------
  42. There are several ways to provide consistency (option `mode`),
  43. depending on the guest type.
  44. .Backup modes for VMs:
  45. `stop` mode::
  46. This mode provides the highest consistency of the backup, at the cost
  47. of a short downtime in the VM operation. It works by executing an
  48. orderly shutdown of the VM, and then runs a background Qemu process to
  49. backup the VM data. After the backup is started, the VM goes to full
  50. operation mode if it was previously running. Consistency is guaranteed
  51. by using the live backup feature.
  52. `suspend` mode::
  53. This mode is provided for compatibility reason, and suspends the VM
  54. before calling the `snapshot` mode. Since suspending the VM results in
  55. a longer downtime and does not necessarily improve the data
  56. consistency, the use of the `snapshot` mode is recommended instead.
  57. `snapshot` mode::
  58. This mode provides the lowest operation downtime, at the cost of a
  59. small inconsistency risk. It works by performing a {pve} live
  60. backup, in which data blocks are copied while the VM is running. If the
  61. guest agent is enabled (`agent: 1`) and running, it calls
  62. `guest-fsfreeze-freeze` and `guest-fsfreeze-thaw` to improve
  63. consistency.
  64. A technical overview of the {pve} live backup for QemuServer can
  65. be found online
  67. NOTE: {pve} live backup provides snapshot-like semantics on any
  68. storage type. It does not require that the underlying storage supports
  69. snapshots. Also please note that since the backups are done via
  70. a background Qemu process, a stopped VM will appear as running for a
  71. short amount of time while the VM disks are being read by Qemu.
  72. However the VM itself is not booted, only its disk(s) are read.
  73. .Backup modes for Containers:
  74. `stop` mode::
  75. Stop the container for the duration of the backup. This potentially
  76. results in a very long downtime.
  77. `suspend` mode::
  78. This mode uses rsync to copy the container data to a temporary
  79. location (see option `--tmpdir`). Then the container is suspended and
  80. a second rsync copies changed files. After that, the container is
  81. started (resumed) again. This results in minimal downtime, but needs
  82. additional space to hold the container copy.
  83. +
  84. When the container is on a local file system and the target storage of
  85. the backup is an NFS/CIFS server, you should set `--tmpdir` to reside on a
  86. local file system too, as this will result in a many fold performance
  87. improvement. Use of a local `tmpdir` is also required if you want to
  88. backup a local container using ACLs in suspend mode if the backup
  89. storage is an NFS server.
  90. `snapshot` mode::
  91. This mode uses the snapshotting facilities of the underlying
  92. storage. First, the container will be suspended to ensure data consistency.
  93. A temporary snapshot of the container's volumes will be made and the
  94. snapshot content will be archived in a tar file. Finally, the temporary
  95. snapshot is deleted again.
  96. NOTE: `snapshot` mode requires that all backed up volumes are on a storage that
  97. supports snapshots. Using the `backup=no` mount point option individual volumes
  98. can be excluded from the backup (and thus this requirement).
  99. // see PVE::VZDump::LXC::prepare()
  100. NOTE: By default additional mount points besides the Root Disk mount point are
  101. not included in backups. For volume mount points you can set the *Backup* option
  102. to include the mount point in the backup. Device and bind mounts are never
  103. backed up as their content is managed outside the {pve} storage library.
  104. Backup File Names
  105. -----------------
  106. Newer versions of vzdump encode the guest type and the
  107. backup time into the filename, for example
  108. vzdump-lxc-105-2009_10_09-11_04_43.tar
  109. That way it is possible to store several backup in the same
  110. directory. The parameter `maxfiles` can be used to specify the
  111. maximum number of backups to keep.
  112. [[vzdump_restore]]
  113. Restore
  114. -------
  115. A backup archive can be restored through the {pve} web GUI or through the
  116. following CLI tools:
  117. `pct restore`:: Container restore utility
  118. `qmrestore`:: Virtual Machine restore utility
  119. For details see the corresponding manual pages.
  120. Bandwidth Limit
  121. ~~~~~~~~~~~~~~~
  122. Restoring one or more big backups may need a lot of resources, especially
  123. storage bandwidth for both reading from the backup storage and writing to
  124. the target storage. This can negatively affect other virtual guests as access
  125. to storage can get congested.
  126. To avoid this you can set bandwidth limits for a backup job. {pve}
  127. implements two kinds of limits for restoring and archive:
  128. * per-restore limit: denotes the maximal amount of bandwidth for
  129. reading from a backup archive
  130. * per-storage write limit: denotes the maximal amount of bandwidth used for
  131. writing to a specific storage
  132. The read limit indirectly affects the write limit, as we cannot write more
  133. than we read. A smaller per-job limit will overwrite a bigger per-storage
  134. limit. A bigger per-job limit will only overwrite the per-storage limit if
  135. you have `Data.Allocate' permissions on the affected storage.
  136. You can use the `--bwlimit <integer>` option from the restore CLI commands
  137. to set up a restore job specific bandwidth limit. Kibit/s is used as unit
  138. for the limit, this means passing `10240' will limit the read speed of the
  139. backup to 10 MiB/s, ensuring that the rest of the possible storage bandwidth
  140. is available for the already running virtual guests, and thus the backup
  141. does not impact their operations.
  142. NOTE: You can use `0` for the `bwlimit` parameter to disable all limits for
  143. a specific restore job. This can be helpful if you need to restore a very
  144. important virtual guest as fast as possible. (Needs `Data.Allocate'
  145. permissions on storage)
  146. Most times your storage's generally available bandwidth stays the same over
  147. time, thus we implemented the possibility to set a default bandwidth limit
  148. per configured storage, this can be done with:
  149. ----
  150. # pvesm set STORAGEID --bwlimit KIBs
  151. ----
  152. Configuration
  153. -------------
  154. Global configuration is stored in `/etc/vzdump.conf`. The file uses a
  155. simple colon separated key/value format. Each line has the following
  156. format:
  157. OPTION: value
  158. Blank lines in the file are ignored, and lines starting with a `#`
  159. character are treated as comments and are also ignored. Values from
  160. this file are used as default, and can be overwritten on the command
  161. line.
  162. We currently support the following options:
  163. include::vzdump.conf.5-opts.adoc[]
  164. .Example `vzdump.conf` Configuration
  165. ----
  166. tmpdir: /mnt/fast_local_disk
  167. storage: my_backup_storage
  168. mode: snapshot
  169. bwlimit: 10000
  170. ----
  171. Hook Scripts
  172. ------------
  173. You can specify a hook script with option `--script`. This script is
  174. called at various phases of the backup process, with parameters
  175. accordingly set. You can find an example in the documentation
  176. directory (``).
  177. File Exclusions
  178. ---------------
  179. NOTE: this option is only available for container backups.
  180. `vzdump` skips the following files by default (disable with the option
  181. `--stdexcludes 0`)
  182. /tmp/?*
  183. /var/tmp/?*
  184. /var/run/?*pid
  185. You can also manually specify (additional) exclude paths, for example:
  186. # vzdump 777 --exclude-path /tmp/ --exclude-path '/var/foo*'
  187. (only excludes tmp directories)
  188. Configuration files are also stored inside the backup archive
  189. (in `./etc/vzdump/`) and will be correctly restored.
  190. Examples
  191. --------
  192. Simply dump guest 777 - no snapshot, just archive the guest private area and
  193. configuration files to the default dump directory (usually
  194. `/var/lib/vz/dump/`).
  195. # vzdump 777
  196. Use rsync and suspend/resume to create a snapshot (minimal downtime).
  197. # vzdump 777 --mode suspend
  198. Backup all guest systems and send notification mails to root and admin.
  199. # vzdump --all --mode suspend --mailto root --mailto admin
  200. Use snapshot mode (no downtime) and non-default dump directory.
  201. # vzdump 777 --dumpdir /mnt/backup --mode snapshot
  202. Backup more than one guest (selectively)
  203. # vzdump 101 102 103 --mailto root
  204. Backup all guests excluding 101 and 102
  205. # vzdump --mode suspend --exclude 101,102
  206. Restore a container to a new CT 600
  207. # pct restore 600 /mnt/backup/vzdump-lxc-777.tar
  208. Restore a QemuServer VM to VM 601
  209. # qmrestore /mnt/backup/vzdump-qemu-888.vma 601
  210. Clone an existing container 101 to a new container 300 with a 4GB root
  211. file system, using pipes
  212. # vzdump 101 --stdout | pct restore --rootfs 4 300 -
  213. ifdef::manvolnum[]
  214. include::pve-copyright.adoc[]
  215. endif::manvolnum[]