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RE: [Xen-devel] clock drift in Xen 4.0.0

To: "Keir Fraser" <keir.fraser@xxxxxxxxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: RE: [Xen-devel] clock drift in Xen 4.0.0
From: "James Harper" <james.harper@xxxxxxxxxxxxxxxx>
Date: Tue, 25 May 2010 17:01:05 +1000
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Thread-topic: [Xen-devel] clock drift in Xen 4.0.0
> On 25/05/2010 07:50, "James Harper" <james.harper@xxxxxxxxxxxxxxxx>
wrote:
> 
> > Are there any known problems with clock drift in Xen 4.0.0? One DomU
> > with an uptime of 49 days is now 7 minutes in front. I never noticed
the
> > problem before I upgraded.
> >
> > /proc/sys/xen/independent_wallclock=0
> 
> Are you running NTP? 100ppm drift isn't unbelievable without external
> synchronisation.
> 

That's 7 minutes in front of the Dom0 that it's sitting on. The Dom0
runs ntp. Another DomU on the same system is ahead by a similar amount
(9 minutes over 74 days). I thought that with independent_wallclock=0
that they should stay in step.

I actually just noticed that I'm running 4.0.0-rc6, not 4.0.0 proper...
d'oh. I think I should probably update before thinking about it much
more.

James


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