[CentOS] Xen clock drift

Jack Bailey jack at internetguy.net
Tue Jan 8 21:18:09 UTC 2008


>
>> badclock# ksh ./xenclockdrift
>> ntpd: time slew -0.000193s
>> ntpd: time set -57.356377s
>> ntpd: time slew +0.002352s
>> ntpd: time slew +0.003018s
>> ntpd: time set -57.417488s
>> ntpd: time slew +0.012089s
>> ntpd: time slew -0.000985s
>>
>> These domains are fully virtualized and set up identically, except
>> "badclock" is allocated two processors versus one processor for
>> "goodclock".  DomU's clock is running normally.
>>     
>
> I'm not sure with Xen, but on VMWare one should not be using NTP at
> all.  Time syncing should be done with the vmware tools and the host,
> with NTP only running on the host (not the guests).  Using NTP on a
> vmware system will result in similar behavior to what you are seeing
> here.

ntpd is not running.  I'm using it here manually to show the clock and 
how it periodically jumps ahead by 57 seconds.

Jack




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