xen vm not keeping date/time properly

George Magklaras georgios at biotek.uio.no
Thu Jan 22 15:52:11 UTC 2009

This page might offer some help:


To recap, we use the 'noselect' keyword to avoid the running ntpd on the 
client to attempt to sync with the defined servers and ntpq does not 
report any disturbing drifts on the client...and we do run ntpd normally 
(no 'noselect') on Dom0.

What happens (happened if you have already tried) if you try and do 
this? And what's your hardware platform?


George Magklaras BSc Hons MPhil

Senior Computer Systems Engineer/UNIX-Linux Systems Administrator
EMBnet Technical Management Board
The Biotechnology Centre of Oslo,
University of Oslo

Ryan Golhar wrote:
> I've seen a ton of messages like this but no solution that works.  I 
> have a 64-bit RHEL 5 machine running multiple guests.  Dom0 keeps time 
> using ntp and works well.
> I initially had the virtual machines do the same thing, but they failed 
> to keep time properly.  I've since disabled ntp on the guests and 
> haven't found a solution.
> I saw messages regarding setting /proc/sys/xen/independent_wallclock to 
> 0, but I only see this file on Dom0, not the guests so I'm not quite 
> sure how this works for the guests keeping proper time.
> Has anyone figured out how to keep 64-bit guests in sync with Dom0?
> Ryan

More information about the redhat-list mailing list