KVM snapshot/live backup for VM with multiple qcow2 files / disk images

czezz · 07-14-2017, 03:40 AM

The procedure to do KVM guest snapshot (live) is quite well described here: http://wiki.libvirt.org/page/Live-di...ve-blockcommit
It describes how to backup VM which is deployed in 1 qcow2 file / disk image.
I have tested that and it works perfectly for me.

Now, I want to try more complicated scenario.
Here is machine that is built with multiple (4) disk images.

Code:

host:~ # virsh domblklist xddVM
Target     Source
------------------------------------------------
vda        /var/lib/libvirt/images/xdd1.qcow2
vdb        /var/lib/libvirt/images/data1_xdd.qcow2
vdc        /var/lib/libvirt/images/data2_xdd.qcow2
vdd        /var/lib/libvirt/images/data3_xdd.qcow2
vde        /var/tmp/xdd1/seed.iso

I wonder what should be the right way/procedure to do live backup in this scenario?
I would try to enable snapshot to each .qcow2. My worry however is that i will not be able to enable snapshot to all of .qcow2 exactly in this same time. Which might lead to inconsistency.
What would you suggest in scenario like this?

jefro · 07-14-2017, 02:27 PM

Windows has had live state backups for quite some time. Very useful. There is at least one commercial linux live state backup that I know of and there is at least one free. I have never used either. http://www.fsarchiver.org/live-backup/

I think that the work on qcow3 is supposed to address live state better.