[CentOS] timekeeping on VM - ntpd running

Brian Mathis brian.mathis at gmail.com
Mon Nov 30 19:08:43 UTC 2009


On Mon, Nov 30, 2009 at 12:14 PM, Thomas Harold <thomas-lists at nybeta.com> wrote:
> On 11/30/2009 11:34 AM, Jonathan Garden wrote:
>> This is really stupid question. But referring to:
>> http://lists.centos.org/pipermail/centos/2009-October/083791.html
>> I don't see any line related to ntpd in my /var/log/messages . Do I need
>> to turn-on ntpd for timekeeping on VMs? Some people say not to use ntpd
>> on VMs for timekeeping or is it ntpdate cron job? Can someone please
>> elaborate on this?
>
> On Xen guests, unless /proc/sys/xen/independent_wallclock is set to 1,
> the DomU will slave itself to the Dom0 clock.  So you probably don't
> need NTP inside the DomU.  Our Dom0 uses ntpd to keep itself
> synchronized with the internal time servers on our LAN.
>
> Whether that is better then using ntpd combined with setting that flag
> to zero... I'm not sure.

The OP link is talking about VMware guests, not Xen.  You can't apply
knowledge from one to the other.


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