X-Git-Url: https://git.proxmox.com/?p=pve-docs.git;a=blobdiff_plain;f=vzdump.adoc;h=5341200652823ddc4dc6d3802b577f231e526adb;hp=5440ae873df1a4c382f4971c8f6d942a1cbba69e;hb=92a08560ce4de841db4a69b9b938677299aebac2;hpb=8e4bb2611daa64720762a9d300b729b846103672 diff --git a/vzdump.adoc b/vzdump.adoc index 5440ae8..5341200 100644 --- a/vzdump.adoc +++ b/vzdump.adoc @@ -25,67 +25,108 @@ 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. -.Backup `mode` for VMs: +{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 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 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 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]. -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. -.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 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. `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 @@ -155,7 +196,6 @@ 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 @@ -186,7 +226,7 @@ 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