Re: [Qemu-devel] Live Block Migration using Mirroring

[Paolo Bonzini]

Il 28/02/2012 18:46, Federico Simoncelli ha scritto:
> > > Thank you for getting this. Being able to have a bogus backing file
> > > was a bonus but it's not really required for the mirrored live block
> > > migration. We can add the support for switching the backing file in the
> > > drive-reopen part.
> > 
> > Wait, it's not really required for oVirt because it creates the
> > snapshot outside QEMU.  What about everyone else?
> 
> They'll have (as oVirt) two mirrored snapshot pointing at the same
> base. The only difference is that the image is created internally, but
> that's not hard.

Can you detail how you are switching the backing file in the
drive-reopen?  Either the BlockDriverState opened by blkmirror, or the
one opened at the end, will have to use the "wrong" backing_file.  How
do you arrange for that?

Paolo