Re: [Qemu-devel] [PATCH 4/6] snapshot: implemention of common API to take snapshots

[Wenchao Xia]

于 2012-12-21 6:19, Eric Blake 写道:
> On 12/17/2012 02:58 AM, Dietmar Maurer wrote:
> > > > > > Seems this makes it impossible to use external commands to make
> > > > > snapshots?
> > > > > >
> > > > >      what command? can you tip more about the case?
> > > >
> > > > For example, nexenta storage provides an API to create snapshots. We
> > > > want to use that. Another example would be to use lvcreate to create lvm
> > > snapshots.
> > > >
> > >     I am not familar with those tools, Patch 5 and 6 provides hmp and qmp API,
> > > hope you can enlight more what is  missing if it can't work with external tool.
> >
> > We need the ability to create snapshots with external tools - your patch does 
> > not support that.
> > I think that is a major drawback.
>
> I think the ability to create snapshots with external tools is going to
> require asynchronous snapshots, where the work is divided into several
> phases.  You'll need qemu to prepare for the snapshot, then the external
> tools to create the snapshot, then resume qemu with possibly different
> file names as a result of the snapshot being created.  I'm certainly
> interested in seeing what you come up with, and how libvirt will be able
> to interact with it for external tool snapshots.

  If libvirt could integrate external tool using code, that would be
great. For qemu, My understanding is just to take internal snapshot
and stop vm, then let management stack do the things remain. Dietmar,
do you think that is all what needed in qemu?

--
Best Regards

Wenchao Xia