On 01/05/2013 01:21 AM, Wenchao Xia wrote: > I guess migration to file makes vm stopped, and lack a step > to take snapshot in the end of migration, also the usage seems > strange makes me feel something is lacking. I'd like to > have: > 1 take blk snapshot internal/external lively. > 2 take vmstate snapshot internal/external lively. > 3 combination.
Libvirt 1.0.1 can already do external live snapshots - it does a live migration to file, and when that finally converges enough to pause, there is less than a second of downtime when libvirt then follows up with an external disk snapshot and then resumes the guest. Of course, this approach requires multiple files, and there is no way to take an internal snapshot with current QMP support. And the point remains in this thread that a live migration to file takes more space than a paused migration, in part because earlier portions of the migration stream are revisited later in the stream as memory pages continue to be touched during the live migration. So a new format for seekable migration to file, different than current migration being usable over a fifo, may indeed allow for less disk space and faster booting when reverting to that vmstate. -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
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