NTP problem - Clock too fast for NTP to keep up?

[Gene Heskett]

On Tuesday 08 February 2005 13:24, Robin Laing wrote:
>Peter Kiem wrote:
>> Hi,
>>
>> I've got a FC3 machine where the system clock ADVANCES at a rapid
>> rate which screws up the services I have running.
>>
>> I've got a hardware router (Snapgear SME575) which exposes an NTP
>> server to my network and I can successfully use ntpdate to update
>> the clock as long as I do it every 2 minutes.
>>
>> In the FC3 machine I have the following ntp.conf
>> /etc/ntp.conf:
>> restrict default nomodify notrap noquery
>> restrict 127.0.0.1
>> server 202.173.151.129
>> driftfile /var/lib/ntp/drift
>> broadcastdelay  0.008
>> keys /etc/ntp/keys
>>
>> When I look at what NTP is doing I see:
>> # ntpq -p
>>      remote           refid      st t when poll reach   delay  
>> offset jitter
>> ==================================================================
>>============
>>
>>  fizban.zordah.n 0.0.0.0          5 u   31   64  377    1.038 
>> -393692 29073.0
>>
>> So from what I can NTP is working and can contact the NTP server
>> on my router but the time is changing so fast NTP cannot keep up?
>>
>> Has anyone experienced/solved this issue?
>
>I looked at mine and I find that the offset and jitter are much
>smaller.  From the following link, the offset should be less.
>
>Now I do remember many years ago reading that if your system time is
>out by to much, it won't be updated.  If your time is out, you may
>have to manually reset it.  Also look at the drift file as if this
> is out, your clock will run at the wrong pace.  You may have to
> delete this file and start again.
>
>http://networking.ringofsaturn.com/Protocols/ntp.php
>http://ldp.paradoxical.co.uk/LDP/sag/html/x2883.html
>
>Also, is your BIOS clock set to UTC or local time?  This makes a
>difference from my experience.  One test to make is to check the
> time in bios, shut the computer down and then check the time in
> bios after an hour.  This will give you an indication if the
> hardware (bios) clock is running and how precise it is.  If it is
> running pretty accurate, then I would suspect that the software
> clock is running fast/slow due to the drift setting.
>
>I used to use "hwclock" in the past.

I too had the fast clock problem, and by tickling the tick counter 
with the 'tickadj' command, was able to stay well within 1 second per 
hour.  The bare command will return the current tick value, default 
is 10000, but I'm curently setting it at 9926 for accurate time 
keeping.  This seems to be 2.6 problem as the default is pretty close 
on a 2.4.29 system running on an elderly TYAN mobo at 500mhz.
 
>--
>Robin Laing

-- 
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