[CentOS-virt] Backing up a running KVM guest

Fri Mar 27 17:10:11 UTC 2009
Julian Price <centos.org at jul17pri.co.uk>

Kai Schaetzl wrote:
> I'm not sure what you mean....
I mean that I am backing up one 32GB virtual disk in one file called 
vm.img or vm.qcow or vm.vhd depending on the virtual disk format.

The advantage is that
- we don't care which operating system is inside the virtual disk file
- We can use the LVM snapshot to ensure that the virtual disk file 
represents a moment in time, and doesn't change during the backup, so it 
is consistent.
- There is no need to hold the database lock during the backup - only at 
the moment the snapshot is started.

The answer to whether this technique works with Xen is answered 'Yes' on 
this page:
They are using their proprietary backup software instead of rsync but 
the technique is essentially the same.