+[[chapter_vzdump]]
ifdef::manvolnum[]
-PVE({manvolnum})
-================
-include::attributes.txt[]
+vzdump(1)
+=========
+:pve-toplevel:
NAME
----
vzdump - Backup Utility for VMs and Containers
-SYNOPSYS
+SYNOPSIS
--------
include::vzdump.1-synopsis.adoc[]
DESCRIPTION
-----------
endif::manvolnum[]
-
ifndef::manvolnum[]
Backup and Restore
==================
-include::attributes.txt[]
+:pve-toplevel:
endif::manvolnum[]
-'vzdump' is a utility to make consistent backups of running guest
-systems. It basically creates an archive of the guest private area,
-which also includes the guest configuration files. 'vzdump' currently
-supports LXC containers and QemuServer VMs. There are several ways to
-provide consistency (option `mode`), depending on the guest type.
+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
+of the backups and downtime of the guest system.
+
+{pve} backups are always full backups - containing the VM/CT
+configuration and all data. Backups can be started via the GUI or via
+the `vzdump` command line tool.
+
+.Backup Storage
+
+Before a backup can run, a backup storage must be defined. Refer to
+the Storage documentation on how to add a storage. A backup storage
+must be a file level storage, as backups are stored as regular files.
+In most situations, using a NFS server is a good way to store backups.
+You can save those backups later to a tape drive, for off-site
+archiving.
+
+.Scheduled Backup
+
+Backup jobs can be scheduled so that they are executed automatically
+on specific days and times, for selectable nodes and guest systems.
+Configuration of scheduled backups is done at the Datacenter level in
+the GUI, which will generate a cron entry in /etc/cron.d/vzdump.
-.Backup `mode` for VMs:
+Backup modes
+------------
+
+There are several ways to provide consistency (option `mode`),
+depending on the guest type.
+
+.Backup modes for VMs:
`stop` mode::
-This first performns a clean shutdown of the VM to make sure it is
-stopped. It then starts the VM in suspended mode and uses the qemu
-backup feature to dump all data. If the VM was running, we start
-(resume) it immediately after starting the qemu backup task. This
-keeps the downtime as low as possible.
+This mode provides the highest consistency of the backup, at the cost
+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::
-This mode does not really make sense for qemu. Please use snapshot
-mode instead.
+This mode is provided for compatibility reason, and suspends the VM
+before calling the `snapshot` mode. Since suspending the VM results in
+a longer downtime and does not necessarily improve the data
+consistency, the use of the `snapshot` mode is recommended instead.
`snapshot` mode::
-This mode simply starts a qemu live backup task. If the guest agent
-is enabled (`agent: 1`) and running, it calls 'guest-fsfreeze-freeze'
-and 'guest-fsfreeze-thaw' to improve consistency.
+This mode provides the lowest operation downtime, at the cost of a
+small inconstancy risk. It works by performing a Proxmox VE 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
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: Qemu backup provides snapshots on any storage type. It does
-not require that the underlying storage supports snapshots.
+NOTE: Proxmox VE live backup provides snapshot-like semantics on any
+storage type. It does not require that the underlying storage supports
+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 `mode` for Containers:
+.Backup modes for Containers:
`stop` mode::
-Stop the container for the duration of the backup. This potentially results in
-a very long downtime.
+Stop the container for the duration of the backup. This potentially
+results in a very long downtime.
`suspend` mode::
This mode uses rsync to copy the container data to a temporary
-location (see option `--tmpdir`). Then the container is suspended and a second
-rsync copies changed files. After that, the container is started (resumed)
-again. This results in minimal downtime, but needs additional space
-to hold the container copy.
+location (see option `--tmpdir`). Then the container is suspended and
+a second rsync copies changed files. After that, the container is
+started (resumed) again. This results in minimal downtime, but needs
+additional space to hold the container copy.
+
-When the container is on a local filesystem and the target storage of the backup
-is an NFS server, you should set `--tmpdir` to reside on a local filesystem 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 storage is an NFS server.
+When the container is on a local file system and the target storage of
+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
+storage is an NFS server.
`snapshot` mode::
This mode uses the snapshotting facilities of the underlying
-storage. A snapshot will be made of the container volume, and the
-snapshot content will be archived in a tar file.
+storage. First, the container will be suspended to ensure data consistency.
+A temporary snapshot of the container's volumes will be made and the
+snapshot content will be archived in a tar file. Finally, the temporary
+snapshot is deleted again.
+
+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).
+// 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
-----------------
directory. The parameter `maxfiles` can be used to specify the
maximum number of backups to keep.
+[[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 effect other virtual guest 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 <integer>` 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 KIBs
+----
+
+
Configuration
-------------
-Global configuration is stored in '/etc/vzdump.conf'. The file uses a
+Global configuration is stored in `/etc/vzdump.conf`. The file uses a
simple colon separated key/value format. Each line has the following
format:
OPTION: value
-Blank lines in the file are ignored, and lines starting with a '#'
+Blank lines in the file are ignored, and lines starting with a `#`
character are treated as comments and are also ignored. Values from
this file are used as default, and can be overwritten on the command
line.
include::vzdump.conf.5-opts.adoc[]
-.Example 'vzdump.conf' Configuration
+.Example `vzdump.conf` Configuration
----
tmpdir: /mnt/fast_local_disk
storage: my_backup_storage
You can specify a hook script with option `--script`. This script is
called at various phases of the backup process, with parameters
accordingly set. You can find an example in the documentation
-directory ('vzdump-hook-script.pl').
+directory (`vzdump-hook-script.pl`).
File Exclusions
---------------
NOTE: this option is only available for container backups.
-'vzdump' skips the following files by default (disable with the option
+`vzdump` skips the following files by default (disable with the option
`--stdexcludes 0`)
- /var/log/?*
/tmp/?*
/var/tmp/?*
/var/run/?*pid
Simply dump guest 777 - no snapshot, just archive the guest private area and
configuration files to the default dump directory (usually
-'/var/lib/vz/dump/').
+`/var/lib/vz/dump/`).
# vzdump 777
# vzdump --all --mode suspend --mailto root --mailto admin
-Use snapshot mode (no downtime).
+Use snapshot mode (no downtime) and non-default dump directory.
# vzdump 777 --dumpdir /mnt/backup --mode snapshot
projects / pve-docs.git / blobdiff