[CentOS] ntpd

Akemi Yagi amyagi at gmail.com
Wed Dec 12 13:14:15 UTC 2007


On Dec 12, 2007 5:07 AM, Blackburn, Marvin <mblackburn at glenraven.com> wrote:
>
> -----Original Message-----
> From: centos-bounces at centos.org [mailto:centos-bounces at centos.org] On Behalf
> Of Luke Dudney
> Sent: Wednesday, December 12, 2007 5:32 AM
> To: CentOS mailing list
> Subject: Re: [CentOS] ntpd
>
> On 12/12/2007 05:50, Jason Pyeron wrote:
> > I am running a server inside of VMWare, and the clock gains ~30 seconds
> > every 1000 seconds or 1.03X.
> >
> > /etc/ntp.conf:
> >
> > server time.intranet.pdinc.us maxpoll 7
> >
> > Ideas? If I cannot get ntpd working, then I will have to resort to a cron
> *
> > * * * * rdate -s time.intranet.pdinc.us
>
> I would love to see some clear, accurate guidance from anyone regarding
> time synchronisation within Linux VMs under VMware. From what I've been
> able to gather, VMware recommend that you disable any in-guest external
> synchronisation (ntp, windows time etc) and use vmware-tools to sync the
> time. For now the approach seems to involve trying random kernel boot
> options and a lot of reboots until you find something that works.
>
> I'd be happy to have my understanding of this issue clarified!
>
> cheers
> Luke
>
> Luke,
> We have had similar problems with vm's running fast.  I was under the same
> impression that you were about
> the recommended method to sync time.  But after working the issue with
> vmware for several months, they backed
> down on their recommendation and stated that they did not recommend using
> both methods togethter: syncing with host AND ntpd.
> They said either would be fine, not both.  This didnt entirely fix my
> problem -- still runs a second or two fast, but much better than before.

I think it is worth trying the kernel-vm (100Hz kernel). It may
rectify the time issue you are experiencing. For details, see:

 http://bugs.centos.org/view.php?id=2189

Akemi



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