[CentOS] timekeeping on VMware guests

Akemi Yagi amyagi at gmail.com
Wed Oct 14 01:28:53 UTC 2009


On Tue, Oct 13, 2009 at 4:34 PM, Ray Van Dolson <rayvd at bludgeon.org> wrote:
> On Tue, Oct 13, 2009 at 04:31:03PM -0700, nate wrote:

>> You should certainly install vmware tools, and enable time sync to
>> the guest. Also don't run an ntp server in a Vmware VM.
>
> This is what I'd always thought, but the VMware KB link[1] referenced
> in the other reply in this thread seems to indicate that best practice
> is to use NTP + kernel w/ clock/divider options (unless it's new enough
> to not need it) and to *not* use the VMware Tools host time sync.
>
> That said, you should certainly still have VMware Tools installed, it
> just sounds like the host time sync is no longer preferred...
>
> Also note that they recommend you remove the local time source in
> ntp.conf...
>
> Ray
>
> [1] http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1006427

Right.  The instructions in the above KB article are contrary to the
tactics we used to employ.  At least one of my VM guests whose clock
was going too fast was corrected by following that KB.

However, there is no one-size-fits-all solution.  The article is the
best effort by VMWare but it does not rectify all cases.  As a matter
of fact, the VMWare techs have helped Red Hat improve the RHEL kernel
by providing patches (as I mentioned in my earlier post).  The details
are in this bugzilla:

https://bugzilla.redhat.com/show_bug.cgi?id=463573

Those patches are now in the -164 kernel.

Akemi


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