Hello,
I just encountered a problem with the current snapshot implementation for
qemu/kvm: To revert back to a snapshot, the domain description must closely
match the domain description when the snapshot was created. If the ram-size
doesn't match or the VM now contains fewer CPUs or contains additional disks,
kvm will either not load the snapshot or the machine will be broken
afterwarts.
Is this a known problem?
Without looking into the implementation details I think saving the full domain
description instead of just a reference to the domain uuid as part of the
snapshot description would work better. Or am I supposed to save the domain
description myself in addition the the data saved
in /var/lib/libvirt/qemu/snapshot/$DOMAIN_NAME/$SNAPSHOT_NAME.xml. I think
this is very important feature, because when you - for example - notice that
you need additional disk space and would like to include an additional block
device, this is your ideal time to take a snapshot you can revert to when you
do something wrong.
Looking at VMware I see that reverting a VM there will not only revert the
disks and ram back to the saved state, but also the description including
name, ram size, etc.
Any comment or advise is appreciated.
Sincerely
Philipp Hahn
--
Philipp Hahn Open Source Software Engineer hahn(a)univention.de
Univention GmbH Linux for Your Business fon: +49 421 22 232- 0
Mary-Somerville-Str.1 28359 Bremen fax: +49 421 22 232-99
http://www.univention.de