Hi Ben, Thanks for your response. See my responses inline. On Wed, Oct 06, 2010 at 03:35:23AM +0100, Ben Hutchings wrote: > On Tue, 2010-10-05 at 09:31 +0100, Mark Adams wrote: > > Package: xen-linux-system-2.6.32-5-xen-amd64 > > Version: 2.6.32-21 > > Severity: important > > > > > > Hi, Did you receive this bug report? I hadn't received a bug ID even > > though receiving the copy of the original report. > > We don't have any other bug report with this description. > > > Likely because the address it was sent from originally was invalid. > > That would explain it. > > > ----------------- > > > > Hi All, > > > > > > > > Im running Xen 4.0.1-rc6 Debian squeeze with pvops 2.6.32-21 kernel. > > > > Today I noticed (when kerberos to the domain controllers stopped > > > > working..) that the clock was 50 minutes out in dom0 -- This caused the > > > > HVM windows domain controllers to have the wrong time. > > > > Since you appear to be in the UK, is it possible that the real-time > clock is set to local time (GMT+1) while Xen expects it to be GMT, or > vice versa?
The clock is set with tzdata as BST yes, it is also set to this in the Windows server 2008 domU. We are using localtime=1 to match the clock in dom0 to domU. > > (This doesn't explain why it's 50 minutes out rather than 1 hour. But > ntpd will refuse to correct a large difference and the local clock may > then drift further.) > > [...] > > Can anyone confirm whether xen controls the time or the kernel? Also > > > > when I corrected the time in dom0 it was still wrong in HVM domU -- How > > > > long does it take for this to propogate? (I rebooted the VM's to correct > > > > it immediately). > > > [...] > > For HVM guests, the hypervisor emulates a standard PC real-time clock > and the guest uses that to initialise the system time, but there is no > way to force an update after the guest has booted unless the guest has > specific support for Xen; I assume Citrix does provide such software for > Windows but I don't know whether it is free software. The citrix WHQL drivers might have this functionality, I don't use them though - prefer the GPL PV drivers! (which don't have any clock support as far as I can tell) > > For PV guests, I assume you can force an update to the guest time using > the Xen management tools. > > Note, I'm just a general kernel maintainer and don't have any great > knowledge of Xen. All good, I have a feeling it might be a kernel issue rather than xen, but I'm still not sure what actually -controls- the time, is it the kernel? I think the key is in the log Oct 2 18:50:33 havhost1 kernel: [623480.977748] Clocksource tsc unstable (delta = -2999660303788 ns) > As this is when the clock went from 18:00 to 18:50 and started the chain of events (restarted the 2008 domU). Any ideas why this log occurred? > Ben. Regards, Mark > > -- > Ben Hutchings > Once a job is fouled up, anything done to improve it makes it worse. -- To UNSUBSCRIBE, email to debian-kernel-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/20101006083331.ga27...@campbell-lange.net
