On Fri, Feb 13, 2015 at 01:03:49PM -0700, Eric Blake wrote: > On 02/13/2015 03:15 AM, Kashyap Chamarthy wrote: > > On Thu, Feb 12, 2015 at 08:41:31PM -0600, Edward Young wrote: > >> Hi all, > >> > >> > >> When I live migrate a vm using > >> > >> "migrate --live --copy-storage-all mig-vm qemu+ssh://192.168.1.3/system > >> tcp://192.168.1.3" > >> > >> > >> I got the following error > >> > >> > >> WARNING: Image format was not specified for > >> 'nbd://node2:49155/drive-virtio-disk0' and probing guessed raw. > >> > >> 258 Automatically detecting the format is dangerous for raw > >> images, write operations on block 0 will be restricted. > >> > >> 259 Specify the 'raw' format explicitly to remove the restrictions. > >> > >> > >> >From the error itself, I can tell that nbd server treat this image as raw, > >> rather than qcow2. My platform is libvirt+qemu. the image type of this vm > >> is indeed qcow2. I do not know how to let nbd know this image format. > > > > Hmm, I wonder if `virsh --migrate` should have a --format (or -F) option > > that one can specify the format. Let's see what Eric Blake and others say. > > No. The format used by the NBD connection under the hood is not > user-visible (for that matter, there may be more than one disk being > migrated, and a single 'migrate --format' would NOT be sufficient to > cover the case where multiple disks for the guest have different formats > on the host). I think that it is merely a case where libvirt itself > needs to explicitly tell qemu that the NBD server it is setting up under > the hood will serve raw data, as there is no mention of the NBD server > on the command line. Thanks for the explanation, it's at-least very clear why the "--format" in this case is not sufficient at all. -- /kashyap _______________________________________________ libvirt-users mailing list libvirt-users@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvirt-users
