On 09/26/2011 08:31 PM, huachao yao wrote:
Hey When I want to take a snapshot for a Domain by using virDomainSnapshotCreateXML. The Error as below happen:
libvir: QEMU error : Requested operation is not valid: Disk '/var/lib/libvirt/images/fedora-qcow.qcow2' does not support snapshotting
Can you also post the XML of the domain, as in 'virsh dumpxml dom'? I suspect that your xml is either omitting the driver type (making libvirt have to probe, if qemu.conf allows probing, which is a security risk), or calling out raw instead of qcow2 (as in the following example): <devices> <disk ...> <driver name='qemu' type='qcow2'/> Libvirt refuses to do system checkpoints with internal disk snapshots if a disk is not explicitly qcow2, which explains the message you are getting.
The snapshot Configuration is : <domainsnapshot> <description>Snapshot of OS install and updates</description> <disks> <disk name='/var/lib'> <source file='/var/lib-snapshot'/> </disk> <disk name='vdb' snapshot='no'/> </disks> </domainsnapshot>
This makes it look like you are trying to do a disk snapshot. Are you passing the VIR_DOMAIN_SNAPSHOT_CREATE_DISK_ONLY flag? If so, your error message doesn't make sense (that requests external snapshots, which don't have a restriction on a qcow2-only source). If not, it means your <disks> designation is being ignored (without the DISK_ONLY flag, you are requesting a system checkpoint, which currently uses internal disk snapshots without regards to any <disks> element).
And /var/lib/libvirt/images/fedora-qcow.qcow2 is the disk for the domain (use qemu-img to create). And I had tried another Disk format (*.img), but the error still happen. how can i deal with this error??
PS:qemu version is 0.14& libvirt version is 0.9.4. Pls help. :-(
Oh, 0.9.4 doesn't have the DISK_ONLY flag, and doesn't know how to parse <disks> in the first place. For that, you need 0.9.5 or newer. -- Eric Blake eblake@redhat.com +1-801-349-2682 Libvirt virtualization library http://libvirt.org