[libvirt-users] RBD snapshots

[Emmanuel Lacour]

Dear libvirt users, I'm stuck on this subject and would appreciate a
working example as this looks a supported feature :)

After many tries and packages backports, here is my current setup:

qemu 2.5
libvirt 3.0
ceph hammer

on Debian jessie.

Here is the relevent domain xml parts:

<disk type='network' device='disk' snapshot='internal'>
      <driver name='qemu' type='raw'/>
      <auth username='libvirt'>
        <secret type='ceph' uuid='xxxxxxxxxxxxxxxx'/>
      </auth>
      <source protocol='rbd' name='libvirt-pool/vm-test'>
        <host name='192.168.253.1' port='6789'/>
        <host name='192.168.253.3' port='6789'/>
        <host name='192.168.253.254' port='6789'/>
        <snapshot name='backup'/>
      </source>
      <backingStore/>
      <target dev='vda' bus='virtio'/>
      <alias name='virtio-disk0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x06'
function='0x0'/>
    </disk>



After several tries, I discovered the snapshot option in source tag, and
that I need to pre-create this snapshot using rbd so the vm can start.

But then I tried:

# virsh snapshot-create-as vm-test
error: unsupported configuration: internal snapshot for disk vda
unsupported for storage type raw


# virsh snapshot-create-as vm-test snap1 --memspec file=/tmp/vm-test.mem
--diskspec vda,snapshot=internal
error: unsupported configuration: internal snapshot for disk vda
unsupported for storage type raw

# virsh snapshot-create-as vm-test snap1 --disk-only --atomic --diskspec
vda,snapshot=internal
error: unsupported configuration: active qemu domains require external
disk snapshots; disk vda requested internal


and some other test, without any success:(


What I just would like to achieve is to do a consistent disk snapshot of
the VM without VM shutdown (suspend is ok) and using virsh as this seems
supported (I can manually run rbd snap create, I know). And if possible
whol mem+disk consistent snapshot without downtime :)

Any hint to make this working, as anyone out ther having succes in such
process?