[ntp:questions] Unexpected ntpd behavior

Pete Buelow nospam at putzin.net
Tue Mar 8 23:55:18 UTC 2005


Some quick background. Trying to get ntpd running on some IA64 hardware in a
pretty simple environment. Two machines in a pair relationship, the first 
machine in the pairing talks to a known good NTP server, the other talks to
it's paired buddy. OS is Debain Sarge stable, ntp is 4.1.0-8. Ntp is
started with -n -c /path/to/conf -x. Conf is simple, and is below.

server 11.0.0.1 prefer
server 127.127.1.1
fudge 127.127.1.1 stratum 14 refid LCL
driftfile /etc/ntp.drift
pidfile /etc/ntp.pid
disable stats
authenticate no

Problem is, if time is slow compared to 11.0.0.1 (which works just fine,
it's a timeserver for several hundred lab machines), it will catch up quite
rapidly (much faster than the 2000s/s rate), and run past. If the time is
ahead of the server, it will just continue ahead. I found a post below
which states that it should then turn around eventually, and head the other
direction, bouncing like a bungee, but I've never run the test that long. I
have no idea why this behavior is happening. And it is the same behavior on
both machines.

A sample ntpq -p output. Clock was set 6 and a half seconds behind 11.0.0.1.

Node2# ntpq -p
     remote           refid      st t when poll reach   delay   offset 
jitter
==============================================================================
*11.0.0.1        192.168.31.253   4 u   55   64  377    0.308  6418.55  
1.565
 LOCAL(1)        LOCAL(1)        14 l   21   64  377    0.000    0.000  
0.004

Two notes of interest based on other posts I've read
1. Our tick rate is 1ms instead of 10ms.
2. On almost all of the test machines, the drift file is populated with the
value 500. On one it's ~450. According to another poster, that could be the
source of some issues.

Thoughts? Ideas? I'm assuming right now that it's either a config or a HW
issue. I'm running a test now with this config and command line options,
but am adding "disable kernel" to the config file. Wondering if that will
change the behavior.

Thanks in advance if anyone has any help to offer at all.
 
-- 
Pete Buelow
replace nospam with putzin if you feel the urge to reply to me directly.



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