[libvirt-users] sanlockd, virtlock and GFS2

Daniel P. Berrange berrange at redhat.com
Fri May 3 13:07:37 UTC 2013


On Fri, May 03, 2013 at 10:10:50AM +0100, Daniel P. Berrange wrote:
> On Fri, May 03, 2013 at 11:07:52AM +0200, Franky Van Liedekerke wrote:
> > On 2013-05-03 10:51, Daniel P. Berrange wrote:
> > >On Fri, May 03, 2013 at 10:39:33AM +0200, Franky Van Liedekerke wrote:
> > >>Virtlockd
> > >>=========
> > >>Since sanlock was not working as expected, I tried virtlockd. This
> > >>seems to be working well, but: live migration fails because the file
> > >>on the shared disk (used for locking) is being locked by the
> > >>original server running the VM. So when trying to do live migration,
> > >>this fails and leaves the VM paused on the original server. Trying
> > >>to migrate a paused server then works ok, but that's of course not
> > >>live migration.
> > >
> > >That would be a bug - the lock is suposed to be released on the
> > >source & re-acquired on the dest at the switch-over point.
> > >
> > >Daniel
> > 
> > Okay ... anyway to test/debug that? Any gfs2 options to take into
> > account? I can recompile virtlockd if wanted ...
> 
> It is unlikley to have anything todo with GFS2. It'll bug a bug hiding
> somewhere in the lock manager or QEMU code I expect. Some sequence of
> operations is not quite right

A rather awful coding screwup caused us to never release locks when the
VM was paused, thus breaking migration

The fix is here

https://www.redhat.com/archives/libvir-list/2013-May/msg00240.html



Daniel
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