Re: [Qemu-devel] [PATCH V2 3/4] blockdev: Allow snapshoting of protocols.

[Benoît Canet]

> base1 [file] --- base1 [qcow2] --- snap1.qcow2 --\
> base2 [file] --- base2 [qcow2] --- snap2.qcow2 --->-- quorum
> base3 [file] --- base3 [qcow2] --- snap3.qcow2 --/

> 
> I think the last one is what you really want, but it's certainly not the
> case that is enabled by this patch.

Yes I am trying to get this configuration: quorum always on top.

Benoît

> 
> >> If qcow2 is specified as the format in the QMP command, why is it then
> >> wrong to try and open the file as qcow2? Why does it fail? What is the
> >> correct driver?
> > 
> > It's correct to format the individual quorum files as qcow2 so specifying 
> > qcow2
> > in the qmp command seems ok.
> > But opening a "quorum:" url which agregate these qcow2 files will fail if 
> > drv is
> > the qcow2 driver.
> > Would passing the quorum protocol driver to bdrv_open be ok ?
> 
> A quorum: URL opened with the qcow2 driver should succeed and result in
> something like the second case mentioned above.
> 
> Kevin