Since the errata kernel release 2.6.18-164.6.1 we have been
seeing Xen domU's that will occasionally jump forward in time by
40-80 minutes.  the behavior is such that the clock will jump
forward and then just sit there until the clock of the underlying
dom0 catches up to it again.

At first we were running ntpd on our domU's but then disabled it
in response to suggestions in several howtos.  So now we know
that the problem has nothing to do with rogue ntp packets but
could very well be something in xen or kernel-xen that is causing it.
There's a report of something very similar in the CentOS forum
to which I've appended more details of this bug.

https://www.centos.org/modules/newbb/viewtopic.php?topic_id=23402

Nothing in the upstream vendor bugzilla about this that I can find,
or nothing in the Xen mailing lists that's obvious.

Any help is appreciated.

Steve Timm


-- 
------------------------------------------------------------------
Steven C. Timm, Ph.D  (630) 840-8525
[log in to unmask]  http://home.fnal.gov/~timm/
Fermilab Computing Division, Scientific Computing Facilities,
Grid Facilities Department, FermiGrid Services Group, Assistant Group Leader.