Hi,
After upgrading to libvirt 0.8.1, I can no longer create empty volumes with no
backing store and an explicit format of qcow2.
This XML volume definition:
<volume>
<name>testserverb-data2.img</name>
<allocation>0</allocation>
<capacity units='G'>20</capacity>
<target>
<format type='qcow2'/>
<permissions>
<owner>107</owner>
<group>107</group>
<mode>0744</mode>
</permissions>
</target>
</volume>
yields the error "Cannot run /usr/bin/qemu-img to create /data/testserverb-
data.img: Invalid argument"
In /var/log/messages on the qemu host I can find the following snippet after
that:
error : virRunWithHook:933 : internal error '/usr/bin/qemu-img create -f qcow2
/data/testserverb-data.img 0K' exited with non-zero status 1 and signal 0:
qemu-img: Image creation needs a size parameter#012
error : virStorageBackendCreateExecCommand:537 : Cannot run /usr/bin/qemu-img
to create /data/testserverb-data.img: Invalid argument
error : qemudClientReadBuf:1653 : gnutls_record_recv: A TLS packet with
unexpected length was received.
If I leave out the <format> element and/or specify a <backingStore> element
for the volume, it works again. (I suppose the backing store makes it work
because in that case qemu-img does not need a size parameter...)
The host system is a vanilla Fedora Core 12 system (aside from the upgraded
libvirt).
Regards,
Guido Winkelmann