[fedora-virt] info on save function in virt-manager

Chris Lalancette clalance at redhat.com
Mon Sep 21 06:28:59 UTC 2009


Gianluca Cecchi wrote:
> Is the save function in virt-manager for a vm equivalent to these steps:
> 
> 1) pause vm (for example in virt-manager gui)
> 2) save disk image to file
> 3) run vm again
> ?
> Is any mem state preserved in this save operation?

It's equivalent to steps 1) and 2), followed by a kill of the paused VM.  And
yes, the memory state is preserved.  On a restore, the memory state is restored,
and the VM is set running again.

The idea behind it is that during host shutdown (or other times), you want to
preserve the state of your guests and then resume them from where they were.

Note very carefully that this is *not* the same as a full snapshot; if you save
a guest, and then restore it multiple times from the same save file, you will
certainly corrupt your disk image.  That is, a save does not take an "snapshot"
of the underlying storage at the same time.  That functionality is planned, but
really needs a new API (and cooperation from the underlying qemu bits) to work
properly.

-- 
Chris Lalancette




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