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Re: clock constantly out of sync

To: lvs-users@xxxxxxxxxxxxxxxxxxxxxx
Subject: Re: clock constantly out of sync
From: Todd Lyons <tlyons@xxxxxxxxxx>
Date: Wed, 16 Nov 2005 09:53:51 -0800
Francois JEANMOUGIN wanted us to know:

>> heartbeat[1234]: info: Clock jumped backwards. Compensating.
>> This occurs because i sync the time via ntpdate every hour. 
>First of all, you have a very bad hardware as far as it can gain 
>seconds in an hour. Anyway, You should use ntpd instead of ntpdate
>And your clock would never be out of sync.

ntp under vmware causes major problems.  The longer it runs, the more it
"compensates" for things.  It jumps back and forth, further and further
each time, until after a few days, it is jumping back and forth *hours*,
wreaking all kind of havoc on a linux system that's using nfs or samba.
I've seen a vmware system that exhibited this with both RedHat and
Gentoo.  The original poster is correct to be using ntpdate instead of
ntp daemon.  It's the only way to keep the time reasonably close.
Personally, I'd tell him to do it more often, such as:
  * * * * * /usr/sbin/ntpdate time.server.com >/dev/null 2>&1
substitute your own internal time server for "time.server.com".

-- 
Regards...              Todd
There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo.  Please use in that order. --Ed Howdershelt
Linux kernel 2.6.12-12mdksmp   3 users,  load average: 0.31, 0.27, 0.29

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