Re: [libvirt-users] Snapshot Error
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(a)redhat.com +1-801-349-2682
Libvirt virtualization library http://libvirt.org