Re: [libvirt-users] libvirt live migration, qcow2 image, nbd server
On 02/12/2015 07:41 PM, 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.
Was that error printed by the source or the destination qemu? It may be
a bug in libvirt for not explicitly requesting raw (we DO want the NBD
server to be raw, but need to be explicit so as to avoid unsafe probing).
>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.
Just because the underlying file on the disk is qcow2 does not impact
what the NBD is serving - the NBD connection MUST be raw, unless you
have a funky situation with a qcow2 file whose contents are also a
nested qcow2 encoding of data.
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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