Backup of a running container with vzdump

Vzdump is a utility to make consistent snapshots of running OpenVZ containers (and KVM virtual machines if you are using Proxmox VE). It basically creates a tar archive of the container's private area, which also includes the CT configuration files.

There are several ways to provide consistency:

• Stop the CT during backup (very long downtime)
• Use rsync and suspend/resume (minimal downtime)
• Use LVM2 (no downtime)

Vzdump stores the backup on the disk in a single file. This file should go to a tape backup for archiving.

Download

Download vzdump rpm or deb packages from http://download.openvz.org/contrib/utils/vzdump/ or for newest version, check http://www.proxmox.com/cms_proxmox/en/technology/oss-software/openvz/

For rpm based systems:

wget http://www.proxmox.com/cms_proxmox/cms/upload/vzdump/vzdump-1.1-2.noarch.rpm

For Debian based systems:

wget http://www.proxmox.com/cms_proxmox/cms/upload/vzdump/vzdump_1.1-2_all.deb

Installation

For rpm based systems:

rpm -i vzdump-1.1-2.noarch.rpm

For Debian based systems:

dpkg -i vzdump_1.1-2_all.deb

Synopsis

see also:

man vzdump

vzdump OPTIONS [--all | <VMID>]

      --exclude VPSID         exclude VPSID (assumes --all)
      --exclude-path REGEX    exclude certain files/directories. You
                              can use this option more than once to specify
                              multiple exclude paths
      --stdexcludes           exclude temorary files and logs
      --compress              compress dump file (gzip)
      --dumpdir DIR           store resulting files in DIR
      --tmpdir DIR            store temporary files in DIR. --suspend and --stop are using this directory to store a copy of the VM.
      --mailto EMAIL          send notification mail to EMAIL. You can use
                              this option more than once to specify multiple
                              receivers
      --stop                  stop/start VPS if running
      --suspend               suspend/resume VPS when running
      --snapshot              use LVM snapshot when running
      --size MB               LVM snapshot size (default 1024)
      --bwlimit KBPS          limit I/O bandwidth; KBytes per second
      --lockwait MINUTES      maximal time to wait for the global
                              lock. vzdump uses a global lock file to make
                              sure that only one instance is running
                              (running sereral instance puts too much load
                              on a server). Default is 180 (3 hours).
      --stopwait MINUTES      maximal time to wait until a VM is stopped.
      --restore FILENAME      restore FILENAME

Examples

Use a running container, for example install this: Proxmox Mail Gateway in container.

Backup

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

vzdump 777

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

vzdump --suspend 777

Backup all containers and send notification mails to root.

vzdump --suspend --all --mailto root

Use LVM2 to create snapshots (no downtime).

vzdump --dumpdir /space/backup --snapshot 777

Note that using LVM2 and vzdump to create snapshots requires 512Mb of free space in your VG as described here.

Restore

Restore the above backup to CT 600:

vzdump --restore /space/backup/vzdump-777.tar 600

Bugs

(not fixed in 1.1-2) The rsync command used by vzdump to create the backup in suspend mode does not support the "--exclude-path" option. So rsync backup the whole VE directory including the paths to ignore, thus making a very big backup.

Workaround: A workaround has been proposed on OpenVZ forum: http://forum.openvz.org/index.php?t=msg&goto=36924&

User: tatawaki
Messages: 3
Registered: December 2008  Junior Member
From: *sbm.shawcable.net

Line 694:
my $rsyncopts = "--stats --numeric-ids --bwlimit=${opt_bwlimit}";

# changes to

my $rsyncopts = "--stats --numeric-ids --bwlimit=${opt_bwlimit}";
$rsyncopts = $rsyncopts." --exclude-from=/home/backups/exclude_vzdump.txt";

the txt file contains <VEID>/home/:

1094/home/
510/opt/
...

(fixed in 1.1-1) vzdump will fail under Debian Etch in version 1.0-2 if it is invoked with parameter "--snapshot" and if the logical volume name contains a hyphen.

Workaround: One possible workaround is to rename the logical volume in question thus it doesn't contain any hyphen. A bug report was sent to proxmox on 02 June 2008. Other distributions or versions may be affected, too.