X-Git-Url: https://git.proxmox.com/?p=pve-docs.git;a=blobdiff_plain;f=vzdump.adoc;h=a2eec20f528af3b5d192081cd75d2c40b96e67d4;hp=4f0d27114ae0ced2a532408c411d76ea42598ae4;hb=c7678c11fd51ef56a7dad30a355024c2cf2acfca;hpb=65647b07977927ade109e116322cc1dc00e6445a diff --git a/vzdump.adoc b/vzdump.adoc index 4f0d271..a2eec20 100644 --- a/vzdump.adoc +++ b/vzdump.adoc @@ -25,46 +25,73 @@ Backup and Restore include::attributes.txt[] 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 requirements 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. Proxmox VE 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 archive. + +.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 modes +------------ +There are several ways to provide consistency (option `mode`), +depending on the guest type. -.Backup `mode` for VMs: +.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 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. `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 copy +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]. -NOTE: Qemu backup provides snapshots on any storage type. It does -not require that the underlying storage supports snapshots. - +NOTE: For VMs, this _snapshot_ mode relates to the fact that the backup is +performed while the VM is running. This has here nothing to do with file systems +snapshots and can be operated on any kind of storage. -.Backup `mode` for Containers: +.Backup modes for Containers: `stop` mode:: -Stop the guest during backup. This 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:: @@ -77,20 +104,29 @@ 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 in `suspend` -mode a local container using ACLs to an NFS server. +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` mountpoint option individual volumes +can be excluded from the backup (and thus this requirement). + +NOTE: bind and device mountpoints are skipped during backup operations, like +volume mountpoints with the backup option disabled. Backup File Names ----------------- -Newer versions of vzdump encode the virtual machine type and the +Newer versions of vzdump encode the guest type and the backup time into the filename, for example vzdump-lxc-105-2009_10_09-11_04_43.tar @@ -149,15 +185,16 @@ directory ('vzdump-hook-script.pl'). File Exclusions --------------- -First, this option is only available for container backups. 'vzdump' -skips the following files with option `--stdexcludes` +NOTE: this option is only available for container backups. + +'vzdump' skips the following files by default (disable with the option +`--stdexcludes 0`) - /var/log/?* /tmp/?* /var/tmp/?* /var/run/?*pid -Or you can manually specify exclude paths, for example: +You can also manually specify (additional) exclude paths, for example: # vzdump 777 --exclude-path /tmp/ --exclude-path '/var/foo*' @@ -183,7 +220,7 @@ Backup all guest systems and send notification mails to root and admin. # 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