[libvirt] question about save/restore domain

[Daniel P. Berrange]

On Wed, Jul 04, 2012 at 12:15:20PM +0200, Christophe Fergeau wrote:
> On Tue, Jul 03, 2012 at 11:44:16PM +0300, Zeeshan Ali (Khattak) wrote:
> > On Tue, Jul 3, 2012 at 9:18 PM, Eric Blake <eblake at redhat.com> wrote:
> > The plan was to do the latter (online cloning) but since its not
> > already possible and IMO it might be too much work for Jovanka to
> > handle within the GSoC timeline (keeping in mind that half of the time
> > is already gone), we can drop the "saving of RAM/state" part for now
> > at least.
> 
> I think "saving of RAM/state" in an appliance (something that is
> distributed to other people) does not go well with <cpu mode="host-model">
> since the other user may have a totally different CPU in his machine. One
> more reason to focus on offline appliances for now ;)

host-model is probably the least of your worries. More critical is that
unless the recipient has the exact same QEMU version, they may well not
even be able to load the saved image. While QEMU does strive for save
restore compatibility across versions, in practice is has been terribly
unreliable & crash-prone. You'd be well served to stay far away from
the idea of passing saved-VM images between people. It can only lead
to pain & suffering.

As mentioned elsewhere in this thread, you don't even want to be
passing around the libvirt XML really. You want to use the disk
image in combination with an appliance format like OVF to describe
its general requirements, rather than the config for a specific
instantiation of the image which is what libvirt XML gives you.

Daniel
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