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Re: [Xen-users] Clock (time) issue

To: xen-users@xxxxxxxxxxxxxxxxxxx
Subject: Re: [Xen-users] Clock (time) issue
From: Mark Adams <mark@xxxxxxxxxxxxxxxxxx>
Date: Tue, 5 Oct 2010 14:02:24 +0100
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No-one had any similar issues?

What do people do to ensure stable time across dom0 and all domU's??

Regards,
Mark

On Mon, Oct 04, 2010 at 01:00:51PM +0100, Mark Adams wrote:
> On Mon, Oct 04, 2010 at 11:01:10AM +0100, Mark Adams wrote:
> > 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.
> > 
> > I'm not sure if this is a kernel issue or a xen issue, but the only
> > thing related is I can see the following in the kernel log:
> > 
> > Oct  2 18:50:33 havhost1 kernel: [623480.977748] Clocksource tsc unstable 
> > (delta = -2999660303788 ns)
> > 
> > But I also see in the dmesg log that xen is using it's own clock.
> > 
> > [    7.676563] Switching to clocksource xen
> > 
> > I can't identify anything else in the logs to indicate when the time
> > might have changed. I have a few other dom0 at the same level that
> > haven't decided to change the time.
> > 
> > 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).
> > 
> > Any other pointers on how to ensure stability of clocks from dom0 to
> > domU HVM hosts (and pv for that matter..) would be appreciated.
> 
> Some further info on this, It appears the HVM domU (windows server 2008)
> unexpectedly shut down at 18:51, after the unstable clocksource error.
> qemu-dm logs show a reset "reset requested in cpu_handle_ioreq." and
> xend.log shows a reboot 
> 
> [2010-10-02 18:51:03 1759] INFO (XendDomainInfo:2088) Domain has shutdown: 
> name=ha-dc1 id=2 reason=reboot.
> 
> This is like someone issuing "xm reboot domain" is it not? Is it
> possible that xen could have issued this reboot itself due to a crash? I
> can't see any crash logs.
> 
> Cheers,
> Mark
> 
> > 
> > Cheers,
> > Mark 
> > 
> > _______________________________________________
> > Xen-users mailing list
> > Xen-users@xxxxxxxxxxxxxxxxxxx
> > http://lists.xensource.com/xen-users
> 
> _______________________________________________
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> Xen-users@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-users


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