Hello,
We are running openstack mitaka in ubuntu 16.04 and storage back-end is
ceph. we have running vms and we want to change from virtio to scsi to
support trimming.
Tried to change xml configuration file via virsh and works only if you
reboot via virsh. when you reboot via nova goes to default
I think you can create empty volumes in cinder command line of the same as
your volume. then delete created volume in ceph. finally rename you volume
with data in ceph to deleted volume name created in cinder
cinder create --name volume_name volume_size
rbd rm pool_name/volume-id_of_cinder_vol
