On Sat, Jan 05, 2013 at 08:28:18PM -0700, Eric Blake wrote: > 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.
Thanks for the explanations Wenchao, Juan, and Eric. Stefan
