Re: [libvirt-users] how to store an internal disk snapshot by use

On 05/29/2012 03:40 AM, Rujie Xu wrote: > Hello everyone, > I am trying to find a way to store an internal disk snapshot and > supposed to restore later. > > Here is the problems I met: > 1) when I use SnapshotCreateXML() to create a disk_only snapshot while > the domain is inactive, there is an error happened: > disk snapshot of inactive domains not implemented yet. > I am wondering is there and way I can save the disk_only snapshot when > the domain is inactive right now? That code still has to be written. It's on my todo list. https://bugzilla.redhat.com/show_bug.cgi?id=817226 That said, if you _don't_ use the disk_only flag and the domain is offline, then the end result right now is that you get internal snapshots for free (since a system checkpoint of an offline domain _is_ the disk snapshot, and since system checkpoint currently uses internal snapshots only). > > 2) also use snapshotCreateXML() to create a disk_only snapshot while > the domain is active, and use the xml to set the <disk name="hda" > snapshot="internal"> there is also an error happened: > unsupported configuration: active qemu domains require external disk > snapshot; disk hda requested internal Correct. Qemu does not support the creation of internal disk snapshots except by the 'savevm' command which takes a system checkpoint snapshot (that is, unless qemu gives us a way to do disk-only internal snapshots of a running VM, you are stuck on this front). > > 3) when I use snapshotCreateXML() to create a disk_only snapshot using > external file, it could be done, but when I try to use revertToSnapshot() > to revert this snapshot there is another error happened: > revert to external snapshot not supported yet. Correct, that's another API that I haven't yet coded; and you're the second person to ask about it this week: https://www.redhat.com/archives/libvirt-users/2012-May/msg00122.html > > Is there anyone can help me about this, or we just can't use libvirt to > managed the disk snapshot right now? Help in contributing code would be very welcome. -- Eric Blake eblake(a)redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org