[ntp:questions] why is my pool server's offset so bad

Danny Mayer mayer at ntp.isc.org
Fri Feb 1 02:33:09 UTC 2008


Pat Farrell wrote:
> On Wed, 30 Jan 2008 23:40:17 -0500, Richard B. Gilbert wrote:
>>> But lately, the offsets are diving down. See
>>> http://www.pool.ntp.org/scores/70.184.242.241
> 
>> Sorry about that.  How about supplying some USEFUL information
>> about your server!  Knowing what O/S you are running on which hardware 
>> platform, what version of ntpd 
> 
> I opened it up for general queries so you can ntpq -p and see.
> 
> Its a debian Etch on a dual Xeon (intel 32) platform.
> ntpd 4.2.2p4
> Its got no real clocks, its just a load sharing device, getting good time
> from overworked upstream ntp servers and sharing it with the world
> 
>> It might be helpful to start with the ntpq -p "banner".
> 
> Don't know what you mean by 'banner'
> here is ntpq -p
> 
> pfarrell at noise:/etc$ ntpq -p 
>      remote           refid      st t when poll reach   delay   offset  jitter
> ==============================================================================
>  ntp-2.cns.vt.ed 198.82.247.40    2 u  31h   64    0   17.908   -0.296   0.000
>  ntp-4.cns.vt.ed 198.82.247.164   2 u  31h   64    0   18.567    0.637   0.000
>  ancalagon.cede. .INIT.          16 u    - 1024    0    0.000    0.000   0.000
>  prometheus.acm. .����.          16 u  31h   64    0    0.000    0.000   0.000
>  time-b.nist.gov .ACTS.           1 u  31h   64    0   13.555    6.162   0.000
> 
> 

You should at least upgrade to 4.2.4. The refid garbage on the line for 
prometheus was fixed a long time ago.

> 
>> It has been my experience that ntpd, when properly configured with good
>> servers and, optionally, a good ref clock, keeps time very well indeed.
> 
> It was my experience that for four or five months, the server scored 20
> constantly. Recently, not so much.

Those numbers above and the ones I got when I queried your server are 
excellent for most purposes. You don't want to see my numbers, though 
admittedly I had hibernated my laptop and ntpd is still recovering right 
now. My stationary systems are much more stable.

Danny



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