Re: Live migration from Xen 3.1.2 to 4.2.3 doesn't work

[Ian Campbell <Ian.Campbell@citrix.com>]

On Thu, 2013-11-14 at 10:28 +0200, Pasi Kärkkäinen wrote:
> On Wed, Nov 13, 2013 at 08:28:10PM +0000, Ian Campbell wrote:
> > On Wed, 2013-11-13 at 19:02 +0000, Jim Durand wrote:
> > > See log errors below, trying to live migrate VM's from Xen 3.1.2 ->
> > > Xen 4.2.3. Perhaps we cannot live migrate across major revs?
> > 
> > See http://wiki.xen.org/wiki/Xen_Version_Compatibility. Normally only N
> > to N+1 is supported. So 3.4.x->4.0.x was supported and 4.1.x->4.2.x is
> > supported etc.
> > 
> > 3.1.2 to 4.2 represents something like 5 releases, I'm afraid that is
> > not supported.
> > 
> > Apart from any issue with migration 3.1.2 is ancient (6 years tomorrow!
> > ), I'm afraid it is no longer supported here.
> > http://wiki.xen.org/wiki/Xen_Maintenance_Releases
> > 
> 
> I'm guessing Xen 3.1.2 in this case is RHEL5 Xen,
> which is not really 3.1.2 .. it has tons of backports from later Xen versions..
> 
> But yeah, live migration from it to recent upstream Xen is not very likely to work..

It demonstrably does not work, which is why Jim is asking...

> At least it hasn't been tested by upstream Xen developers.

Indeed not.

In theory it ought to be possible to install and migrate to each of the
intervening half a dozen or so versions of Xen in turn.

However in practical terms I think you'd be better off scheduling some
down time and rebooting the VM onto the new version.

Ian.