[ntp:questions] how will this effect stability

Uwe Klein uwe_klein_habertwedt at t-online.de
Fri Feb 16 09:53:37 UTC 2007


Terje Mathisen wrote:
> Uwe Klein wrote:
> 
>> Terje Mathisen wrote:
>>
>>> Please let huffpuff run for a few days while plotting frequency and 
>>> offset values, my guess is it will turn out to be darn stable. :-)
>>>
>>> Terje
>>>
>> some data to gloat over:
>> huffpuff is at 160000 added ~19:00 on the 14th
>> t-online was added later.
>>
>> t-online.png is the ntp server of my provicer ntp1.t-online.de over dsl
>> ptb.png is the same to ptbtime1.ptb.de , dsl and then some more hops
>> robert.png is to another host on the local network.10Base100
>>
>> http:// home.foni.net/ ~kuttersegeln/ntp/
> 
> 
> So, are you happy with those results?
I am holding my breath.

( one thing I noticed this morning is that ntpd hops between
   the two Stratum 1 servers )

( wouldn't a Kalman Filter Type approach work better with
   time sources of comparable quality? )

enabled more logging and wrote some scripts to collect and plot data.
going to post some more images tonight.

One thing I noticed is that logfile statements position in the config
file is significant.
i.e. when logfile stuff ist last in the config the initialisation
logging goes to default ( syslog )
Does the same apply to things like the "tinker" stuff?


> 
> You will always see horrible delay/offset values, but the local clock 
> should coast over those periods, keeping the local frequency pretty stable.
> 
> In fact, plotting the clock frequency numbers alongside the other values 
> would be a very nice way to determine if/when things have stabilized.
> 
> You should see either a straight line, or a sawtooth/sinus curve which 
> corresponds to the air condition in your server room.
I kept the heating on this night, at its permanent location later on temp
ist kept ~ constant ( central heating, no climate control ).
> 
> Terje
G!&Tks
uwe

> 




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