Re: [Qemu-devel] [PATCH v4 0/6] Efficient VM backup for qemu

[Dietmar Maurer]

> On Wed, Feb 20, 2013 at 04:04:49PM +0000, Dietmar Maurer wrote:
> > > The backup writer abstraction is a special case interface somewhere
> > > between an image format and live migration.  I'd prefer it if the
> > > backup block job stuck to BlockDriverState as the destination for backup
> data.
> > > Then you could save a point-in-time copy of a disk to a raw or even
> > > qcow2 image.
> >
> > backup needs to work on non-seekable pipes.
> 
> In _your_ use case. That means that we should support using non-seekable
> pipes, but it doesn't mean that any other use case is irrelevant. In fact I 
> think
> backing up to a normal raw or qcow2 image file is the interesting case for the
> majority of people.

VMs can have more than one disk. How do you backup them into a single raw or 
qcow2 image?
And where do you store the configuration inside a qcow2 file?