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Date: Thu, 15 May 2008 15:39:19 -0700 (PDT)
From: Luke Dean <LukeD@pobox.com>
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To: Christopher Cowart <ccowart@rescomp.berkeley.edu>
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Subject: Re: time drift
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On Thu, 15 May 2008, Christopher Cowart wrote:

> David Kelly wrote:
>> Its PC commodity-grade. Not all that unusual even for stuff sold
>> claiming to be a "server". This is in no small part why ntpd exists.
>>
>> nptd calculates a correction coefficient and (under FreeBSD) stores it
>> in /var/db/ntpd.drift for use on next start so as to more quickly
>> establish a lock.
>>
>> So in short ntpd calibrates your clock in order to minimize the
>> corrections required. Is The Right Thing To Do.
>
> We run a large number of FreeBSD servers under vmware. We've seen ntpd
> silently die, because the drift becomes "insane." What do others do in
> this situation? (We've resorted to croning ntpdate for VMs.)

kern.hz="100"
in /boot/loader.conf solved this problem for me.