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Re: [Xen-users] DomU clock out of sync

To: Dmitry Nedospasov <dmitry@xxxxxxxxx>
Subject: Re: [Xen-users] DomU clock out of sync
From: Joseph Glanville <joseph.glanville@xxxxxxxxxxxxxx>
Date: Sat, 14 May 2011 21:18:25 +1000
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Ensure that ntpdate or ntpd is adjusting the hwclock in the dom0 as
this is what is passed through to guests.


On 14 May 2011 21:05, Dmitry Nedospasov <dmitry@xxxxxxxxx> wrote:
> Hey all,
> I was watching some logs on a domU today and i suddenly noticed that the
> timestamps were off by something on the order of 47 seconds. I was
> surprised because *I don't* run independent wall clocks. I checked
> some other domUs and the "drift" was also very close to that of the
> first domU.
> I also checked another dom0, Here the domUs were "only" out of sync by
> ~11 seconds.
> The dom0s are all debian squeeze with Xen 4.0.1-2. The domUs are also
> debian squeeze and utilizing PV with the ParaVirtOPs in the normal
> debian linux-image-2.6.32 kernel.
> I am currently using ntpdate (in cron.hourly) on my dom0s, could this be
> the problem? Is there a difference in the way ntpdate updates time the
> way ntpd does? IIRC ntpd updates time continuously, correct?
> Can someone explain why this would happen. Could this be caused by a
> xend restart?
> After googling, I'm surprised a best practice solution isn't listed on
> XenFaq...  considering how many users seem to be frustrated with this
> issue.
> All the best,
> D.
> --
> Dmitry Nedospasov <dmitry@xxxxxxxxx> -- Twitter: @nedos
> Web: http://nedos.net -- Github: http://github.com/nedos
> _______________________________________________
> Xen-users mailing list
> Xen-users@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-users

Kind regards,
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Orion Virtualisation Solutions | www.orionvm.com.au | Phone: 1300 56
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