xen vm not keeping date/time properly

Jose R R jose.r.r at metztli.com
Fri Jan 23 06:58:18 UTC 2009

2009/1/22 Ryan Golhar <golharam at umdnj.edu>:
> 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.

Those organizations that offer Virtual Private Servers (VPS) would not
be in business if they had not found a solution to the problem you
describe ;)  As an instance, using such technologies as HyperVM (<
http://lxlabs.com/software/hypervm/ >) they offer their clients *any*
of a variety of Xen DomU GNU/Linux distributions.

You may want to try the following procedure (from an CentOS list):

----------Begin fragment-------------------------------

Put this in /etc/sysctl.conf :

xen.independent_wallclock = 1

and then execute sysctl.

What happens then is that the domU will do it's own timekeeping and no
longer follow the dom0. Now this also means that you need to run a
ntpd inside the domU to make sure it's clock keeps syncronised.
-----------End Fragment---------------------------------
< http://lists.centos.org/pipermail/centos-virt/2008-January/000185.html >

Best regards.

Jose R R
IBM Lotus Symphony is officially supported on Red Hat, SuSE, and
Ubuntu GNU/Linux

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