Hi Wido, I checked the source code. For RBD network devices, it should work well.
In com.cloud.hypervisor.kvm.resource.LibvirtComputingResource.createVbd(Connect, VirtualMachineTO, String, LibvirtVMDef) disk.defNetworkBasedDisk(physicalDisk.getPath().replace("rbd:", "") so disk.getPath() returns the path like /mnt/pool_uuid/disk_path. I just committed a patch to support RBD on disk_io_stat branch which is not needed, I will revert it. -Wei