Date: Fri, 18 Dec 2009 12:24:50 -0500 From: Steve Polyack <korvus@comcast.net> To: Chuck Swiger <cswiger@mac.com> Cc: Robert Fitzpatrick <robert@webtent.com>, FreeBSD <freebsd-questions@freebsd.org> Subject: Re: slow clock on FreeBSD 7.2 on vmware Message-ID: <4B2BBAE2.6090102@comcast.net> In-Reply-To: <4B2AA541.5010304@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>
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On 12/17/09 16:40, Steve Polyack wrote:
> On 12/17/09 16:23, Chuck Swiger wrote:
>> The "kern.hz=100" recommendation I can certainly agree with, but
>> there is mostly no point in running ntpd or variants anywhere except
>> on the host machine ("host ESX" for VMware, or Dom0 for Xen). For
>> VMware, the vmtools stuff should provide a mechanism to sync time in
>> VMs to the host clock.
>>
> 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. 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.
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