vzdump1

Usage

Overview

vzdump is an utility to make consistent snapshots of running virtual machines (VMs). It basically creates a tar archive of the VM private area, which also includes the VM configuration files. vzdump currently supports OpenVZ and QemuServer VMs.

There are several ways to provide consistency:

"stop" mode

Stop the VM during backup. This results in a very long downtime.

"suspend" mode

For OpenVZ, this mode uses rsync to copy the VM to a temporary location (see option --tmpdir). Then the VM is suspended and a second rsync copies changed files. After that, the VM is started (resume) again. This results in a minimal downtime, but needs additional space to hold the VM copy.

For QemuServer, this mode work like "stop" mode, but uses suspend/resume instead of stop/start.

"snapshot" mode

This mode uses LVM2 snapshots. There is no downtime, but snapshot mode needs LVM2 and some free space on the corresponding volume group to create the LVM snapshot.

Backup file names

Newer version of vzdump encodes the virtual machine type and the backup time into the filename, for example

 vzdump-openvz-105-2009_10_09-11_04_43.tar

That way it is possible to store several backup into the same directory. The parameter "maxfiles" can be used to specify the maximal number of backups to keep.

Restore

The resulting tar files can be restored with the following programs.

vzrestore: OpenVZ restore utility

qmrestore: QemuServer restore utility

For details see the corresponding manual pages.

Configuration

Global configuration is stored in /etc/vzdump.conf.

 tmpdir: DIR
 dumpdir: DIR
 storage: STORAGE_ID
 mode: snapshot|suspend|stop
 bwlimit: KBPS
 lockwait: MINUTES 
 stopwait: MINUTES 
 size: MB
 maxfiles: N
 script: FILENAME

Hook script

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 ("hook-script.pl").

EXCLUSIONS (OpenVZ only)

vzdump skips the following files wit option --stdexcludes

 /var/log/.+
 /tmp/.+
 /var/tmp/.+
 /var/run/.+pid

You can manually specify exclude paths, for example:

> vzdump --exclude-path "/tmp/.+" --exclude-path "/var/tmp/.+" 777

(only excludes tmp directories)

Configuration files are also stored inside the backup archive (/etc/vzdump), and will be correctly restored.

Limitations

VZDump does not save ACLs.

Examples

Simply dump VM 777 - no snapshot, just archive the VM private area and configuration files to the default dump directory (usually /vz/dump/).

> vzdump 777

Use rsync and suspend/resume to create an snapshot (minimal downtime).

> vzdump --suspend 777

Backup all VMs and send notification mails to root.

> vzdump --suspend --all --mailto root

Use LVM2 to create snapshots (no downtime).

> vzdump --dumpdir /mnt/backup --snapshot 777

Backup all VMs excluding VM 101 and 102

> vzdump --suspend --exclude 101 --exclude 102

Restore an OpenVZ machine to VM 600

> vzrestore /mnt/backup/vzdump-openvz-777.tar 600

Restore an Qemu/KVM machine to VM 601

> qmrestore /mnt/backup/vzdump-qemu-888.tar 601

Copyright and disclaimer

Copyright (C) 2007-2009 Proxmox Server Solutions GmbH

Copyright: vzdump is under GNU GPL, the GNU General Public License.

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; version 2 dated June, 1991.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.