Re: Migrating volumes to RBD/Ceph

On Sun, Feb 04, 2024 at 20:31:33 +1100, Julian Calaby wrote: > Hi, > > I have a fancy new Ceph cluster and have configured a storage pool > using it in libvirt. I have a bunch of disk images in a "filesystem > directory" storage pool. I want to migrate those disk images into the > RBD pool. > > What is the process for doing this? [...] > 2. virsh blockcopy This is the proper way to do it for any running VM as it's the only approach which preserves data consistency from VM writes, as well as updates XMLs. > No idea how to actually achieve what I want here as it doesn't seem > capable of copying to a non-file destination. 'virsh blockcopy' does in fact support non-file destinations by passing the XML description identical to the <disk> element via the --xml argument. The XML for ceph/rbd should look like: <disk type='network'> <driver name="qemu" type="raw"/> <source protocol="rbd" name="image_name2"> <host name="hostname" port="7000"/> <auth username='myuser'> <secret type='ceph' usage='mypassid'/> </auth> </source> </disk> To run the blockcopy operation and then subsequently switch to the new image after it finishes additional arguments will be needed: virsh blockcopy --domain $VMNAME --path $SOURCEDISKTARGET --xml /path/to/xml --transient-job --verbose --pivot

I don't recall now whether you might need to pre-create the properly-sized rbd volume in ceph or qemu can do that for you.