[ntp:questions] NTP vs chrony comparison (Was: oscillations in ntp clock synchronization)

Petri Kaukasoina kaukasoina708n8s6l3g0 at sci.fi
Sat Jan 26 10:14:30 UTC 2008

David Woolley  <david at ex.djwhome.demon.co.uk.invalid> wrote:
>Petri Kaukasoina wrote:
>> Basically, it stepped time with ntpdate, slept 100 seconds and stepped time
>> again with ntpdate. From the time adjustment, the script calculated the
>> drift value and put that to the drift file. Again, the time offset always
>> stays below 1 ms.
>That has quite a lot of similarity with what ntpd itself does if it is 
>cold started with iburst.  The only big difference is that it uses 900, 
>rather than 100 seconds.  I don't know if that is the same 900 as 
>controlled by "tinker stepout", but, even if it is, the side effect on 
>stepout's would probably be undesirable.  To cold start you need to 
>delete the drift file, or not configure it.

Hmm, I can't see that. I put in only one good time source with iburst,
deleted the drift file and started ntpd. The time offset just keeps growing
and the frequency changes in very small steps. Now, after 30 minutes time is
already 25 ms off and the frequency is only 1.5 ppm (the correct value would
be about 25 ppm).

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