Il 12/12/2012 10:03, Dietmar Maurer ha scritto: >>> So our snapshot implementation uses the following steps: >>> >>> 1.) qmp: savevm-start [statefile] >>> >>> This save the VM state into [statefile] and then stops the VM. >> >> That's migrate exec:cat>statefile (or similar) > > We save to block devices, so we need to allocate them in advance > with a size of 2 x 'memory size'. > So we have an upper limit for the state file file, i.e. we stop the > VM if ('statefile size' > 'assigned memory').
This is a heuristic that we can add (though remember you'll need some extra space for the device state). > It would be great to have some other means to reduce state size (instead > of stopping the VM), for example by slowing down the VM somehow? Yes, you can use the cpu cgroup. Paolo > Any other ideas? >