Re: Storing command line options in qcow2 images

Daniel P. Berrange
2007-08-07T13:50:29Z

On Tue, Aug 07, 2007 at 07:10:17AM +0300, Avi Kivity wrote:
> Anthony Liguori wrote:
> > I don't think adding annotations as snapshots is the right approach. I
> > think proper support should be added in the header. I wouldn't be too
> > concerned with breaking compatibility in qcow2. That's why it's qcow2
> > and not just an updated version of qcow, qcow2 is still, AFAIK, open for
> > breakage.
> >
>
> Are all the users' images open for breakage too?

I'd say not. QCow2 has been around for a long time now so breaking compat
with existing images would be a very bad idea. Ideally though some extension
would be both backwards & forwards compatible - eg existing qcow2 impls
would just ignore any new extension, while new impls would work any image
with or without extension. If this isn't possible then at least call any
new format qcow3 to make it obvious to users that it is not compatible.

Dan.
--
|=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=|
|=- Perl modules: http://search.cpan.org/~danberr/ -=|
|=- Projects: http://freshmeat.net/~danielpb/ -=|
|=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=|