Re: [libvirt] [Qemu-devel] [RFC] qcow3 format in libvirt

Am 04.03.2013 um 14:09 hat Daniel P. Berrange geschrieben: > On Mon, Mar 04, 2013 at 01:58:12PM +0100, Ján Tomko wrote: > > Before posting another version of my patches [1], attempting to add > > support for the new qcow format to libvirt, I would like to know if this > > sounds reasonable: > > > > A new format named 'qcow3' would be added, along with a <features> > > sub-element for target. > > > > <volume> > > <name>qcow3test</name> > > <source> > > </source> > > <capacity unit='GiB'>8</capacity> > > <target> > > <path>/var/lib/libvirt/images/qcow3test</path> > > <format type='qcow3'/> > > <features> > > <lazy_refcounts/> > > </features> > > </target> > > </volume> > > > > I think that libvirt shouldn't care if the features are compatible or > > incompatible, as we don't know what features are supported by the > > hypervisor. Would the features be any good as tri-state (on, off, default?). > > > > While the qcow3 format is handled by the qcow2 driver in QEMU, > > <driver name='qemu' type='qcow2'/> should be enough for domains, > > We should use qcow3 everywhere IMHO, regardless of whether qcow2 > technically works in this context. I think it makes much more sense to deal with it the way qemu does instead of inventing new names. This has much more of an (incompatible) feature flag than of a different image format. So to fit it in your proposed syntax:

But I guess you call all VMDKs just "vmdk", despite the fact that they are really just a collection of different subformats. Right?