WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

Re: [Xen-devel] Xen 3.1.2 domU clock goes out of sync

To: Tõnu Raitviir <jussuf@xxxxxxxx>
Subject: Re: [Xen-devel] Xen 3.1.2 domU clock goes out of sync
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Tue, 20 Nov 2007 23:07:17 +0000
Cc: xen-devel@xxxxxxxxxxxxxxxxxxx
Delivery-date: Tue, 20 Nov 2007 15:02:20 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <20071120220347.O23014@xxxxxxxxxxxxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: Acgryhg7Vp3mGpe9EdyZBAAWy6hiGQ==
Thread-topic: [Xen-devel] Xen 3.1.2 domU clock goes out of sync
User-agent: Microsoft-Entourage/11.3.6.070618
On 20/11/07 21:52, "Tõnu Raitviir" <jussuf@xxxxxxxx> wrote:

>> I wonder if dom0 has remembered some ntp-derived adjustment values despite
>> ntpd no longer running. That would explain why it continues to keep good
>> time while all others drift.
> 
> Well... in the example in my first letter dom0 was booted without ntpd and
> after 2+ days its clock offset was only -0.438055 while domU had drifted
> far away. In that case there was no adjustment values to remember.

Could it not be a drift? e.g., Perhaps you ran ntpdate in dom0 but not the
domUs?

>> So... running ntpd in dom0 is a good idea. :-)
> 
> I don't question that. But I wonder, isn't domU clock supposed to be
> always in sync with dom0, with or without ntpd? Or how exactly does ntpd
> in dom0 affect domU clock?

dom0 updates Xen's shared notion of wallclock time periodically, but only if
dom0 is locked onto ntp.

 -- Keir



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel