On Fri, Feb 12, 2021 at 12:13:58 +0000, Daniel P. Berrangé wrote: > On Fri, Feb 12, 2021 at 11:55:36AM +0100, Peter Krempa wrote: > > On Fri, Feb 12, 2021 at 10:49:02 +0000, Daniel Berrange wrote: > > > On Thu, Feb 11, 2021 at 04:37:47PM +0100, Peter Krempa wrote: > > > > Format the new volumes with 'compat=1.1' since the minimum supported > > > > qemu version is now 1.5 rather the pre-historic compat=0.10. > > > > > > I understand the desire to do this, but this is none the less a > > > semantic change to the behaviour of the APIs. It is the same > > > situation as arbitrarily changing the defaults for any part of > > > the domain XML. > > > > I'm aware of that, but at certain point it IMO doesn't make sense to try > > to stick with a prehistoric format just for the sake of it and IMO this > > is it. > > Well that's a policy decision and it is upto the user or mgmt app to > decide when they wish to drop compatibility with old distros. RHEL > had continued to publish its cloud images with old format until very > recently for sake of compat. I don't think libvirt should be forcing > that decision onto people as it sabotages libvirt's value of providing > long term stable behaviour to applications.
The oldest QEMU release we support understands v3 so there's no reason to use an older format in this respect. But you're right there might be other use cases which would still need v2 format for compatibility. I guess I was too focused on our usage and libvirt/QEMU compatibility when reviewing the patch. Jirka
