[fedora-virt] live migration from CentOS 6.2 to 6.1 fails

[Eric Blake]

On 01/18/2012 03:18 AM, Gianluca Cecchi wrote:
> symbol "--->" corresponds to live migration
> 
> 6.1 --> 6.1 ok
> 6.1 --> 6.2 ok
> 6.2 --> 6.2 ok

Yes, those are all supported migration patterns.

> 
> but
> 
> 6.2 --> 6.1 ko

This is expected - there is no guarantee of downgrade compatibility,
only upgrade compatibility.  The qemu on 6.2 has different machine
models for 6.1 vs. 6.2 hosting, so that it can continue to run a guest
migrated in from a 6.1 host.  But if a guest is started from scratch on
6.2 rather than migrated in from 6.1, then chances are quite high that
the state of the machine will be using 6.2 features that are not
understood by 6.1, and thus you can't migrate to a downgraded qemu.

-- 
Eric Blake   eblake at redhat.com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 620 bytes
Desc: OpenPGP digital signature
URL: <http://lists.fedoraproject.org/pipermail/virt/attachments/20120118/e2ad9086/attachment.sig>