[libvirt] Question about QCOW2 and Libvirt Storage Pools

[Solly Ross]

Hi,
I'm doing some work getting libvirt storage pools into OpenStack, as they definitely
make certain operations much easier for the Nova libvirt driver.  However, one thing
I noticed is that since storage pools automatically refresh on reboot, initial creation
information gets lost.  This poses a problem, since libvirt probes for file type for the
filesystem-based pools (dir, fs, netfs, etc), and can erroneously detect a RAW file as
another file type (for instance, QCOW2).  Is there a reason libvirt doesn't have an option
to persist (to disk) the unchanging parts of the volume XML?

Best Regards,
Solly Ross

P.S. we currently deal with a similar problem in OpenStack by saving the file type to disk
the first time we use the image file.  However, it would be nice if libvirt could handle
this for us, at some point, as it seems like it would be a good thing to have in libvirt.