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Date:      Fri, 18 Dec 2009 09:39:01 -0800
From:      Chuck Swiger <cswiger@mac.com>
To:        Steve Polyack <korvus@comcast.net>
Cc:        Robert Fitzpatrick <robert@webtent.com>, FreeBSD <freebsd-questions@freebsd.org>
Subject:   Re: slow clock on FreeBSD 7.2 on vmware
Message-ID:  <78DA6E6C-85F4-444C-8176-5BAFA6EA32EB@mac.com>
In-Reply-To: <4B2BBAE2.6090102@comcast.net>
References:  <4B23CD8A.50203@webtent.com> <op.u4zhl8bq5wvplz@jam-laptop> <4B291EB5.5040605@webtent.com> <4B2A9C1E.2010509@comcast.net> <3D62B3FC-1385-47C2-A9F3-F81D1597D9A6@mac.com> <4B2AA541.5010304@comcast.net> <4B2BBAE2.6090102@comcast.net>

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Hi--

On Dec 18, 2009, at 9:24 AM, Steve Polyack wrote:
>> I haven't used Xen, but for ESX: I may be wrong, but I'm pretty sure that the vmtools available for FreeBSD do not support synchronizing the host time to the guest OS.  I know it is supported (and works) for Linux, but by what mechanism I do not know.  On OpenBSD the kernel can be built to present a device which will use the "synchronize time with guest" feature of VMware to provide a clock source which can be specified in ntpd.conf.
>> 
>> Perhaps you're right and all it takes is the switch in ESX.  I've disabled ntpd on one of my VMs and I'll see if it drifts any by tomorrow.
> 
> FYI the system has started to drift on the order of 100ms every 6 hours.

OK.

> This leads me to believe that the "synchronize time with guest" feature of ESXi is not sufficient in FreeBSD with VMware tools.  While using NTP, the system would reliably keep in sync within 30ms of local NTP relays.

You supposedly need to re-run it periodically or enable an internal in some .vmx config file; see "Enabling Periodic Synchronization":

  http://www.vmware.com/pdf/vmware_timekeeping.pdf

If this doesn't work in FreeBSD guest VMs, has anyone filed a bug report with them?

Regards,
-- 
-Chuck




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