[ale] Clock Drift in VMware Server

Michael H. Warfield mhw at WittsEnd.com
Thu May 28 22:47:06 EDT 2009


On Thu, 2009-05-28 at 16:53 -0400, Chris Fowler wrote:
> I'm running VMware Server 2.0 on Centos 5.2 and I have 5.2 guests.  The
> clock drift on the guests is horrible.  I've written a script that
> updates the clock

	I'm not sure about Server 2.0 but I worked with the VMware guys on
earlier versions.  It's been a while since I've had to deal with this.

	IIRC...  The conclusion we came to was to disabled apm and acpi in the
kernel on the kernel command line in grub.  Then use the VMware guest
tools to maintain synchronization (I think).

	There may have been one or two others which I ended up using ntpd to
manage the time.  Do not use polling in a cronjob.  Set up an ntp daemon
on a server of your own (it can be the host system) and synchronize to
your favorite stratum 1 or stratum 2 servers or to the ntp pool.  Then,
synchronize all your guests to YOUR ntp server using ntpd (NOT ntpdate).
They should then be able to maintain the clock drift with reasonable
tolerance.  One thing I have not tried, but should certainly work, would
be to set up your master ntpd as a multicast chimer and have your guests
listening to the multicast broadcasts.

	Either way...  Disable apm and acpi in the guests.

> 28 May 10:34:51 ntpdate[4522]: step time server 198.137.202.16 offset
> 558.557700 sec
> 28 May 11:43:41 ntpdate[12168]: step time server 216.14.97.75 offset
> 525.761734 sec
> 28 May 12:49:42 ntpdate[19722]: step time server 69.31.13.210 offset
> 357.566419 sec
> 28 May 13:54:41 ntpdate[27432]: step time server 209.104.4.231 offset
> 298.270392 sec
> 28 May 15:01:02 ntpdate[2459]: step time server 66.79.148.39 offset
> 378.376557 sec
> 28 May 16:08:38 ntpdate[10010]: step time server 207.171.30.106 offset
> 454.967227 sec


> It runs every hour but look at that drift.  Is there anything I can do
> to remedy this?

> Chris

	Regards,
	Mike
-- 
Michael H. Warfield (AI4NB) | (770) 985-6132 |  mhw at WittsEnd.com
   /\/\|=mhw=|\/\/          | (678) 463-0932 |  http://www.wittsend.com/mhw/
   NIC whois: MHW9          | An optimist believes we live in the best of all
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