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80c0adcb | 1 | [[chapter_vzdump]] |
82b4917a | 2 | ifdef::manvolnum[] |
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3 | vzdump(1) |
4 | ========= | |
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5 | :pve-toplevel: |
6 | ||
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7 | NAME |
8 | ---- | |
9 | ||
10 | vzdump - Backup Utility for VMs and Containers | |
11 | ||
12 | ||
49a5e11c | 13 | SYNOPSIS |
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14 | -------- |
15 | ||
16 | include::vzdump.1-synopsis.adoc[] | |
17 | ||
18 | ||
19 | DESCRIPTION | |
20 | ----------- | |
21 | endif::manvolnum[] | |
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22 | ifndef::manvolnum[] |
23 | Backup and Restore | |
24 | ================== | |
5f09af76 | 25 | :pve-toplevel: |
194d2f29 | 26 | endif::manvolnum[] |
5f09af76 | 27 | |
a35aad4a | 28 | Backups are a requirement for any sensible IT deployment, and {pve} |
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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. | |
33 | ||
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. | |
12b04941 | 37 | |
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38 | .Backup Storage |
39 | ||
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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 | |
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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. | |
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44 | You can save those backups later to a tape drive, for off-site |
45 | archiving. | |
12b04941 | 46 | |
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47 | .Scheduled Backup |
48 | ||
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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. | |
12b04941 | 53 | |
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54 | Backup modes |
55 | ------------ | |
94e50bf6 | 56 | |
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57 | There are several ways to provide consistency (option `mode`), |
58 | depending on the guest type. | |
82b4917a | 59 | |
c7678c11 | 60 | .Backup modes for VMs: |
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61 | |
62 | `stop` mode:: | |
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63 | |
64 | This mode provides the highest consistency of the backup, at the cost | |
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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. | |
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70 | |
71 | `suspend` mode:: | |
72 | ||
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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. | |
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77 | |
78 | `snapshot` mode:: | |
79 | ||
94e50bf6 | 80 | This mode provides the lowest operation downtime, at the cost of a |
64caa401 | 81 | small inconsistency risk. It works by performing a {pve} live |
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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 | |
8c1189b6 | 84 | `guest-fsfreeze-freeze` and `guest-fsfreeze-thaw` to improve |
c7678c11 | 85 | consistency. |
01d37422 | 86 | |
64caa401 | 87 | A technical overview of the {pve} live backup for QemuServer can |
01d37422 | 88 | be found online |
d929c5a6 | 89 | https://git.proxmox.com/?p=pve-qemu.git;a=blob_plain;f=backup.txt[here]. |
01d37422 | 90 | |
64caa401 | 91 | NOTE: {pve} live backup provides snapshot-like semantics on any |
94e50bf6 | 92 | storage type. It does not require that the underlying storage supports |
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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. | |
01d37422 | 97 | |
c7678c11 | 98 | .Backup modes for Containers: |
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99 | |
100 | `stop` mode:: | |
101 | ||
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102 | Stop the container for the duration of the backup. This potentially |
103 | results in a very long downtime. | |
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104 | |
105 | `suspend` mode:: | |
106 | ||
01d37422 | 107 | This mode uses rsync to copy the container data to a temporary |
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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. | |
0006064d | 112 | + |
5eba0743 | 113 | When the container is on a local file system and the target storage of |
de14ebff | 114 | the backup is an NFS/CIFS server, you should set `--tmpdir` to reside on a |
5eba0743 | 115 | local file system too, as this will result in a many fold performance |
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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. | |
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119 | |
120 | `snapshot` mode:: | |
121 | ||
01d37422 | 122 | This mode uses the snapshotting facilities of the underlying |
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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. | |
127 | ||
128 | NOTE: `snapshot` mode requires that all backed up volumes are on a storage that | |
8c1189b6 | 129 | supports snapshots. Using the `backup=no` mount point option individual volumes |
b74af7b6 | 130 | can be excluded from the backup (and thus this requirement). |
82b4917a | 131 | |
1eeff3be | 132 | // see PVE::VZDump::LXC::prepare() |
470d4313 | 133 | NOTE: By default additional mount points besides the Root Disk mount point are |
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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. | |
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137 | |
138 | Backup File Names | |
139 | ----------------- | |
140 | ||
8e4bb261 | 141 | Newer versions of vzdump encode the guest type and the |
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142 | backup time into the filename, for example |
143 | ||
144 | vzdump-lxc-105-2009_10_09-11_04_43.tar | |
145 | ||
871e1fd6 | 146 | That way it is possible to store several backup in the same |
82b4917a | 147 | directory. The parameter `maxfiles` can be used to specify the |
871e1fd6 | 148 | maximum number of backups to keep. |
82b4917a | 149 | |
4edb84ec AA |
150 | Backup File Compression |
151 | ----------------------- | |
152 | ||
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]. | |
159 | ||
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. | |
163 | ||
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. | |
169 | ||
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. | |
172 | ||
173 | |=== | |
174 | |.zst | Zstandard (zstd) compression | |
175 | |.gz or .tgz | gzip compression | |
176 | |.lzo | lzo compression | |
177 | |=== | |
178 | ||
179 | If the backup file name doesn't end with one of the above file extensions, then | |
180 | it was not compressed by vzdump. | |
181 | ||
182 | ||
922569a5 | 183 | [[vzdump_restore]] |
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184 | Restore |
185 | ------- | |
186 | ||
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187 | A backup archive can be restored through the {pve} web GUI or through the |
188 | following CLI tools: | |
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189 | |
190 | ||
871e1fd6 | 191 | `pct restore`:: Container restore utility |
82b4917a | 192 | |
922569a5 | 193 | `qmrestore`:: Virtual Machine restore utility |
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194 | |
195 | For details see the corresponding manual pages. | |
196 | ||
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197 | Bandwidth Limit |
198 | ~~~~~~~~~~~~~~~ | |
199 | ||
200 | Restoring one or more big backups may need a lot of resources, especially | |
201 | storage bandwidth for both reading from the backup storage and writing to | |
b26b1d12 | 202 | the target storage. This can negatively affect other virtual guests as access |
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203 | to storage can get congested. |
204 | ||
205 | To avoid this you can set bandwidth limits for a backup job. {pve} | |
3802f512 | 206 | implements two kinds of limits for restoring and archive: |
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207 | |
208 | * per-restore limit: denotes the maximal amount of bandwidth for | |
209 | reading from a backup archive | |
210 | ||
211 | * per-storage write limit: denotes the maximal amount of bandwidth used for | |
212 | writing to a specific storage | |
213 | ||
214 | The read limit indirectly affects the write limit, as we cannot write more | |
215 | than we read. A smaller per-job limit will overwrite a bigger per-storage | |
216 | limit. A bigger per-job limit will only overwrite the per-storage limit if | |
217 | you have `Data.Allocate' permissions on the affected storage. | |
218 | ||
219 | You can use the `--bwlimit <integer>` option from the restore CLI commands | |
220 | to set up a restore job specific bandwidth limit. Kibit/s is used as unit | |
3802f512 | 221 | for the limit, this means passing `10240' will limit the read speed of the |
922569a5 | 222 | backup to 10 MiB/s, ensuring that the rest of the possible storage bandwidth |
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223 | is available for the already running virtual guests, and thus the backup |
224 | does not impact their operations. | |
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225 | |
226 | NOTE: You can use `0` for the `bwlimit` parameter to disable all limits for | |
227 | a specific restore job. This can be helpful if you need to restore a very | |
3802f512 | 228 | important virtual guest as fast as possible. (Needs `Data.Allocate' |
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229 | permissions on storage) |
230 | ||
231 | Most times your storage's generally available bandwidth stays the same over | |
232 | time, thus we implemented the possibility to set a default bandwidth limit | |
233 | per configured storage, this can be done with: | |
234 | ||
235 | ---- | |
b03b8bb6 | 236 | # pvesm set STORAGEID --bwlimit restore=KIBs |
922569a5 TL |
237 | ---- |
238 | ||
4edb84ec | 239 | [[vzdump_configuration]] |
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240 | Configuration |
241 | ------------- | |
242 | ||
8c1189b6 | 243 | Global configuration is stored in `/etc/vzdump.conf`. The file uses a |
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244 | simple colon separated key/value format. Each line has the following |
245 | format: | |
246 | ||
247 | OPTION: value | |
248 | ||
8c1189b6 | 249 | Blank lines in the file are ignored, and lines starting with a `#` |
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250 | character are treated as comments and are also ignored. Values from |
251 | this file are used as default, and can be overwritten on the command | |
252 | line. | |
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253 | |
254 | We currently support the following options: | |
255 | ||
256 | include::vzdump.conf.5-opts.adoc[] | |
257 | ||
258 | ||
8c1189b6 | 259 | .Example `vzdump.conf` Configuration |
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260 | ---- |
261 | tmpdir: /mnt/fast_local_disk | |
262 | storage: my_backup_storage | |
263 | mode: snapshot | |
264 | bwlimit: 10000 | |
265 | ---- | |
82b4917a DM |
266 | |
267 | Hook Scripts | |
268 | ------------ | |
269 | ||
270 | You can specify a hook script with option `--script`. This script is | |
271 | called at various phases of the backup process, with parameters | |
272 | accordingly set. You can find an example in the documentation | |
8c1189b6 | 273 | directory (`vzdump-hook-script.pl`). |
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274 | |
275 | File Exclusions | |
276 | --------------- | |
277 | ||
8e4bb261 FG |
278 | NOTE: this option is only available for container backups. |
279 | ||
8c1189b6 | 280 | `vzdump` skips the following files by default (disable with the option |
8e4bb261 | 281 | `--stdexcludes 0`) |
82b4917a | 282 | |
bf01f882 WB |
283 | /tmp/?* |
284 | /var/tmp/?* | |
285 | /var/run/?*pid | |
82b4917a | 286 | |
8e4bb261 | 287 | You can also manually specify (additional) exclude paths, for example: |
82b4917a | 288 | |
bf01f882 | 289 | # vzdump 777 --exclude-path /tmp/ --exclude-path '/var/foo*' |
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290 | |
291 | (only excludes tmp directories) | |
292 | ||
293 | Configuration files are also stored inside the backup archive | |
65647b07 | 294 | (in `./etc/vzdump/`) and will be correctly restored. |
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295 | |
296 | Examples | |
297 | -------- | |
298 | ||
c31f32a9 | 299 | Simply dump guest 777 - no snapshot, just archive the guest private area and |
82b4917a | 300 | configuration files to the default dump directory (usually |
8c1189b6 | 301 | `/var/lib/vz/dump/`). |
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302 | |
303 | # vzdump 777 | |
304 | ||
871e1fd6 | 305 | Use rsync and suspend/resume to create a snapshot (minimal downtime). |
82b4917a DM |
306 | |
307 | # vzdump 777 --mode suspend | |
308 | ||
c31f32a9 | 309 | Backup all guest systems and send notification mails to root and admin. |
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310 | |
311 | # vzdump --all --mode suspend --mailto root --mailto admin | |
312 | ||
b74af7b6 | 313 | Use snapshot mode (no downtime) and non-default dump directory. |
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314 | |
315 | # vzdump 777 --dumpdir /mnt/backup --mode snapshot | |
316 | ||
c31f32a9 | 317 | Backup more than one guest (selectively) |
82b4917a DM |
318 | |
319 | # vzdump 101 102 103 --mailto root | |
320 | ||
c31f32a9 | 321 | Backup all guests excluding 101 and 102 |
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322 | |
323 | # vzdump --mode suspend --exclude 101,102 | |
324 | ||
c31f32a9 | 325 | Restore a container to a new CT 600 |
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326 | |
327 | # pct restore 600 /mnt/backup/vzdump-lxc-777.tar | |
328 | ||
c31f32a9 | 329 | Restore a QemuServer VM to VM 601 |
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330 | |
331 | # qmrestore /mnt/backup/vzdump-qemu-888.vma 601 | |
332 | ||
333 | Clone an existing container 101 to a new container 300 with a 4GB root | |
334 | file system, using pipes | |
335 | ||
336 | # vzdump 101 --stdout | pct restore --rootfs 4 300 - | |
337 | ||
338 | ||
339 | ifdef::manvolnum[] | |
340 | include::pve-copyright.adoc[] | |
341 | endif::manvolnum[] | |
342 |