Re: [Qemu-devel] [Qemu-block] Some question about savem/qcow2 incremental snapshot

[Stefan Hajnoczi]

On Mon, May 14, 2018 at 02:48:47PM +0100, Stefan Hajnoczi wrote:
> On Fri, May 11, 2018 at 07:25:31PM +0200, Kevin Wolf wrote:
> > Am 10.05.2018 um 10:26 hat Stefan Hajnoczi geschrieben:
> > > On Wed, May 09, 2018 at 07:54:31PM +0200, Max Reitz wrote:
> > > > On 2018-05-09 12:16, Stefan Hajnoczi wrote:
> > > > > On Tue, May 08, 2018 at 05:03:09PM +0200, Kevin Wolf wrote:
> > > > >> Am 08.05.2018 um 16:41 hat Eric Blake geschrieben:
> > > > >>> On 12/25/2017 01:33 AM, He Junyan wrote:
> > > > >> I think it makes sense to invest some effort into such interfaces, 
> > > > >> but
> > > > >> be prepared for a long journey.
> > > > > 
> > > > > I like the suggestion but it needs to be followed up with a concrete
> > > > > design that is feasible and fair for Junyan and others to implement.
> > > > > Otherwise the "long journey" is really just a way of rejecting this
> > > > > feature.

The discussion on NVDIMM via the block layer has runs its course.  It
would be a big project and I don't think it's fair to ask Junyan to
implement it.

My understanding is this patch series doesn't modify the qcow2 on-disk
file format.  Rather, it just uses existing qcow2 mechanisms and extends
live migration to identify the NVDIMM state state region to share the
clusters.

Since this feature does not involve qcow2 format changes and is just an
optimization (dirty blocks still need to be allocated), it can be
removed from QEMU in the future if a better alternative becomes
available.

Junyan: Can you rebase the series and send a new revision?

Kevin and Max: Does this sound alright?

Stefan

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