X-Git-Url: https://git.proxmox.com/?p=pve-docs.git;a=blobdiff_plain;f=vzdump.adoc;h=94536849c206e2e9169731d541a10093df5b086a;hp=97bdcf2efae4132516e230c9e1402333d2369a75;hb=43530f6fe44c20926717a95e02aa19400ad2409c;hpb=49a5e11cd14742d8ad28116fab7fce9fc85321bd diff --git a/vzdump.adoc b/vzdump.adoc index 97bdcf2..9453684 100644 --- a/vzdump.adoc +++ b/vzdump.adoc @@ -1,7 +1,8 @@ +[[chapter_vzdump]] ifdef::manvolnum[] -PVE({manvolnum}) -================ -include::attributes.txt[] +vzdump(1) +========= +:pve-toplevel: NAME ---- @@ -18,14 +19,13 @@ include::vzdump.1-synopsis.adoc[] DESCRIPTION ----------- endif::manvolnum[] - ifndef::manvolnum[] Backup and Restore ================== -include::attributes.txt[] +:pve-toplevel: endif::manvolnum[] -Backups are a requirements for any sensible IT deployment, and {pve} +Backups are a requirement for any sensible IT deployment, and {pve} provides a fully integrated solution, using the capabilities of each storage and each guest system type. This allows the system administrator to fine tune via the `mode` option between consistency @@ -62,10 +62,11 @@ depending on the guest type. `stop` mode:: This mode provides the highest consistency of the backup, at the cost -of a downtime in the VM operation. It works by executing an orderly -shutdown of the VM, and then runs a background Qemu process to backup -the VM data. After the backup is complete, the Qemu process resumes -the VM to full operation mode if it was previously running. +of a short downtime in the VM operation. It works by executing an +orderly shutdown of the VM, and then runs a background Qemu process to +backup the VM data. After the backup is started, the VM goes to full +operation mode if it was previously running. Consistency is guaranteed +by using the live backup feature. `suspend` mode:: @@ -77,19 +78,22 @@ consistency, the use of the `snapshot` mode is recommended instead. `snapshot` mode:: This mode provides the lowest operation downtime, at the cost of a -small inconstancy risk. It works by performing a Proxmox VE live +small inconsistency risk. It works by performing a {pve} live backup, in which data blocks are copied while the VM is running. If the guest agent is enabled (`agent: 1`) and running, it calls `guest-fsfreeze-freeze` and `guest-fsfreeze-thaw` to improve consistency. -A technical overview of the Proxmox VE live backup for QemuServer can +A technical overview of the {pve} live backup for QemuServer can be found online -https://git.proxmox.com/?p=pve-qemu-kvm.git;a=blob;f=backup.txt[here]. +https://git.proxmox.com/?p=pve-qemu.git;a=blob_plain;f=backup.txt[here]. -NOTE: Proxmox VE live backup provides snapshot-like semantics on any +NOTE: {pve} live backup provides snapshot-like semantics on any storage type. It does not require that the underlying storage supports -snapshots. +snapshots. Also please note that since the backups are done via +a background Qemu process, a stopped VM will appear as running for a +short amount of time while the VM disks are being read by Qemu. +However the VM itself is not booted, only its disk(s) are read. .Backup modes for Containers: @@ -107,7 +111,7 @@ started (resumed) again. This results in minimal downtime, but needs additional space to hold the container copy. + When the container is on a local file system and the target storage of -the backup is an NFS server, you should set `--tmpdir` to reside on a +the backup is an NFS/CIFS server, you should set `--tmpdir` to reside on a local file system too, as this will result in a many fold performance improvement. Use of a local `tmpdir` is also required if you want to backup a local container using ACLs in suspend mode if the backup @@ -125,9 +129,11 @@ NOTE: `snapshot` mode requires that all backed up volumes are on a storage that supports snapshots. Using the `backup=no` mount point option individual volumes can be excluded from the backup (and thus this requirement). -NOTE: bind and device mount points are skipped during backup operations, like -volume mount points with the backup option disabled. - +// see PVE::VZDump::LXC::prepare() +NOTE: By default additional mount points besides the Root Disk mount point are +not included in backups. For volume mount points you can set the *Backup* option +to include the mount point in the backup. Device and bind mounts are never +backed up as their content is managed outside the {pve} storage library. Backup File Names ----------------- @@ -137,22 +143,201 @@ backup time into the filename, for example vzdump-lxc-105-2009_10_09-11_04_43.tar -That way it is possible to store several backup in the same -directory. The parameter `maxfiles` can be used to specify the -maximum number of backups to keep. +That way it is possible to store several backup in the same directory. You can +limit the number of backups that are kept with various retention options, see +the xref:vzdump_retention[Backup Retention] section below. + +Backup File Compression +----------------------- + +The backup file can be compressed with one of the following algorithms: `lzo` +footnote:[Lempel–Ziv–Oberhumer a lossless data compression algorithm +https://en.wikipedia.org/wiki/Lempel-Ziv-Oberhumer], `gzip` footnote:[gzip - +based on the DEFLATE algorithm https://en.wikipedia.org/wiki/Gzip] or `zstd` +footnote:[Zstandard a lossless data compression algorithm +https://en.wikipedia.org/wiki/Zstandard]. + +Currently, Zstandard (zstd) is the fastest of these three algorithms. +Multi-threading is another advantage of zstd over lzo and gzip. Lzo and gzip +are more widely used and often installed by default. + +You can install pigz footnote:[pigz - parallel implementation of gzip +https://zlib.net/pigz/] as a drop-in replacement for gzip to provide better +performance due to multi-threading. For pigz & zstd, the amount of +threads/cores can be adjusted. See the +xref:vzdump_configuration[configuration options] below. + +The extension of the backup file name can usually be used to determine which +compression algorithm has been used to create the backup. + +|=== +|.zst | Zstandard (zstd) compression +|.gz or .tgz | gzip compression +|.lzo | lzo compression +|=== + +If the backup file name doesn't end with one of the above file extensions, then +it was not compressed by vzdump. + +Backup Encryption +----------------- + +For Proxmox Backup Server storages, you can optionally set up client-side +encryption of backups, see xref:storage_pbs_encryption[the corresponding section.] + +[[vzdump_retention]] +Backup Retention +---------------- + +With the `prune-backups` option you can specify which backups you want to keep +in a flexible manner. The following retention options are available: + +`keep-all ` :: +Keep all backups. If this is `true`, no other options can be set. + +`keep-last ` :: +Keep the last `` backups. + +`keep-hourly ` :: +Keep backups for the last `` hours. If there is more than one +backup for a single hour, only the latest is kept. + +`keep-daily ` :: +Keep backups for the last `` days. If there is more than one +backup for a single day, only the latest is kept. + +`keep-weekly ` :: +Keep backups for the last `` weeks. If there is more than one +backup for a single week, only the latest is kept. + +NOTE: Weeks start on Monday and end on Sunday. The software uses the +`ISO week date`-system and handles weeks at the end of the year correctly. + +`keep-monthly ` :: +Keep backups for the last `` months. If there is more than one +backup for a single month, only the latest is kept. + +`keep-yearly ` :: +Keep backups for the last `` years. If there is more than one +backup for a single year, only the latest is kept. + +The retention options are processed in the order given above. Each option +only covers backups within its time period. The next option does not take care +of already covered backups. It will only consider older backups. + +Specify the retention options you want to use as a +comma-separated list, for example: + + # vzdump 777 --prune-backups keep-last=3,keep-daily=13,keep-yearly=9 + +While you can pass `prune-backups` directly to `vzdump`, it is often more +sensible to configure the setting on the storage level, which can be done via +the web interface. + +NOTE: The old `maxfiles` option is deprecated and should be replaced either by +`keep-last` or, in case `maxfiles` was `0` for unlimited retention, by +`keep-all`. + +Prune Simulator +~~~~~~~~~~~~~~~ + +You can use the https://pbs.proxmox.com/docs/prune-simulator[prune simulator +of the Proxmox Backup Server documentation] to explore the effect of different +retention options with various backup schedules. + +Retention Settings Example +~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The backup frequency and retention of old backups may depend on how often data +changes, and how important an older state may be, in a specific work load. +When backups act as a company's document archive, there may also be legal +requirements for how long backups must be kept. + +For this example, we assume that you are doing daily backups, have a retention +period of 10 years, and the period between backups stored gradually grows. + +`keep-last=3` - even if only daily backups are taken, an admin may want to + create an extra one just before or after a big upgrade. Setting keep-last + ensures this. + +`keep-hourly` is not set - for daily backups this is not relevant. You cover + extra manual backups already, with keep-last. + +`keep-daily=13` - together with keep-last, which covers at least one + day, this ensures that you have at least two weeks of backups. + +`keep-weekly=8` - ensures that you have at least two full months of + weekly backups. + +`keep-monthly=11` - together with the previous keep settings, this + ensures that you have at least a year of monthly backups. + +`keep-yearly=9` - this is for the long term archive. As you covered the + current year with the previous options, you would set this to nine for the + remaining ones, giving you a total of at least 10 years of coverage. + +We recommend that you use a higher retention period than is minimally required +by your environment; you can always reduce it if you find it is unnecessarily +high, but you cannot recreate backups once they have been removed. + +[[vzdump_restore]] Restore ------- -The resulting archive files can be restored with the following programs. +A backup archive can be restored through the {pve} web GUI or through the +following CLI tools: `pct restore`:: Container restore utility -`qmrestore`:: QemuServer restore utility +`qmrestore`:: Virtual Machine restore utility For details see the corresponding manual pages. +Bandwidth Limit +~~~~~~~~~~~~~~~ + +Restoring one or more big backups may need a lot of resources, especially +storage bandwidth for both reading from the backup storage and writing to +the target storage. This can negatively affect other virtual guests as access +to storage can get congested. + +To avoid this you can set bandwidth limits for a backup job. {pve} +implements two kinds of limits for restoring and archive: + +* per-restore limit: denotes the maximal amount of bandwidth for + reading from a backup archive + +* per-storage write limit: denotes the maximal amount of bandwidth used for + writing to a specific storage + +The read limit indirectly affects the write limit, as we cannot write more +than we read. A smaller per-job limit will overwrite a bigger per-storage +limit. A bigger per-job limit will only overwrite the per-storage limit if +you have `Data.Allocate' permissions on the affected storage. + +You can use the `--bwlimit ` option from the restore CLI commands +to set up a restore job specific bandwidth limit. Kibit/s is used as unit +for the limit, this means passing `10240' will limit the read speed of the +backup to 10 MiB/s, ensuring that the rest of the possible storage bandwidth +is available for the already running virtual guests, and thus the backup +does not impact their operations. + +NOTE: You can use `0` for the `bwlimit` parameter to disable all limits for +a specific restore job. This can be helpful if you need to restore a very +important virtual guest as fast as possible. (Needs `Data.Allocate' +permissions on storage) + +Most times your storage's generally available bandwidth stays the same over +time, thus we implemented the possibility to set a default bandwidth limit +per configured storage, this can be done with: + +---- +# pvesm set STORAGEID --bwlimit restore=KIBs +---- + +[[vzdump_configuration]] Configuration ------------- @@ -204,7 +389,16 @@ You can also manually specify (additional) exclude paths, for example: # vzdump 777 --exclude-path /tmp/ --exclude-path '/var/foo*' -(only excludes tmp directories) +excludes the directory `/tmp/` and any file or directory named `/var/foo`, +`/var/foobar`, and so on. + +Paths that do not start with a `/` are not anchored to the container's root, +but will match relative to any subdirectory. For example: + + # vzdump 777 --exclude-path bar + +excludes any file or directoy named `/bar`, `/var/bar`, `/var/foo/bar`, and +so on, but not `/bar2`. Configuration files are also stored inside the backup archive (in `./etc/vzdump/`) and will be correctly restored.