[K12OSN] NTP Sync

Burroughs, Henry HBurroughs at HHPREP.ORG
Wed Dec 6 13:45:07 UTC 2006


I've had similar issues under VMware (ESX).  First thing, disable NTP.
Make sure you have VMware tools installed under Linux (we are going to
use it's time sync abilities).  You can either use the GUI part of the
tools (ssh -X root at servername) so you can run it on your display, or
just set 

tools.syncTime = "TRUE"

in the config file for your virtual machine (.vmx)

I also would add

clock=pit to the kernel parameters in /boot/grub/grub.conf (we want a
basic clock that doesn't try to overcompensate for the loss of ticks).

Finally, reboot and then we should get the system and hardware clock's

date -s "-1 hour" will drop the clock back an hour....
date -s "-15 minutes" will drop the clock back 15 minutes....

(I'm not that good w/ the date command)..... but get your server's date
clock in sync with whatever time you want...

Then run hwclock --systohc (which will sync the linux clock w/ the vm
hardware clock).  You should be fine now.

Henry Burroughs
Technology Director
Hilton Head Preparatory School

---Original Message---------
Date: Tue, 5 Dec 2006 10:54:04 -0800
From: "Mel Wade" <mel at melwade.com>
Subject: [K12OSN] NTP Sync
To: "Support list for open source software in schools."
	<k12osn at redhat.com>
	<43080f460612051054o5abc4df9y99fc0c83d32d6236 at mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

I'm running K12LSTP 6 on a VMware virutal server.  My time sync is WAY
off when syncing to a Win DC or an external time server.  I seem to
running at about 1/2 speed.

Any help would be appreciated.

[root at library ~]# ntpq -p
     remote           refid      st t when poll reach   delay   offset
======    3 u   27   64    7    0.915  65231.3
64643.2         4 u   25   64    7    1.974  1032.70

This is after about 1 sec:

[root at library ~]# ntpdate -u
 5 Dec 10:53:24 ntpdate[23938]: adjust time server offset
0.495167 sec

Mel Wade
"The real problem is not whether machines think but whether men do." -
BF Skinner http://www.melwade.com

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