ok, I see, thank you very much for your kindly reply, the answer is very clear and useful for me. Thanks a lot! <div class="gmail_quote">2012/5/29 Eric Blake <<a href="mailto:eblake@redhat.com" target="_blank">eblake@redhat.com</a>> <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="im">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? </div>That code still has to be written. It's on my todo list. <a href="https://bugzilla.redhat.com/show_bug.cgi?id=817226" target="_blank">https://bugzilla.redhat.com/show_bug.cgi?id=817226</a> 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). <div class="im"> > > 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 </div>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). <div class="im"> > > 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. </div>Correct, that's another API that I haven't yet coded; and you're the second person to ask about it this week: <a href="https://www.redhat.com/archives/libvirt-users/2012-May/msg00122.html" target="_blank">https://www.redhat.com/archives/libvirt-users/2012-May/msg00122.html</a> <div class="im"> > > Is there anyone can help me about this, or we just can't use libvirt to > managed the disk snapshot right now? </div>Help in contributing code would be very welcome. -- Eric Blake <a href="mailto:eblake@redhat.com">eblake@redhat.com</a> <a href="tel:%2B1-919-301-3266" value="+19193013266">+1-919-301-3266</a> Libvirt virtualization library <a href="http://libvirt.org" target="_blank">http://libvirt.org</a> </blockquote></div> <div> </div>-- Regards, Roger Xu