isn't this possible with virsh snapshot ?   1. virsh snapshot --domain vm (creates a second vdisk.img and make future writes to this vdisk) (it also points to this vdisk in the .xml file) 2. backup the vm original vdisk.img (no writes take place to this vdisk because of step 1, so "consistent state" ?) 3. virsh blokcommit --domain vm (merge snapshot vdisk to original vdisk, after that deletes the snapshot, and points the orginal vdisk back in .xml)   URL of Actual c