[ntp:questions] NTP makes a time jump

unruh unruh at invalid.ca
Thu Jul 11 06:35:02 UTC 2013


On 2013-07-11, karpekin at gmail.com <karpekin at gmail.com> wrote:
> Hello,
> Clients indeed followed server after 2.5 hours. 
> This night they managed to come from -15s difference to +2.5s and now it seems trying to slew another direction. They will probably need another half a day to stop oscillations and finally come to zero. Pity I can't attach a trend picture here, looks pretty funny.
> The only doubt I have is the initial 2.5 hours delay. Server rushed away from clients by ~8 seconds. Clients also moved away from each other a bit, but still max was 480 ms. So the system didn't make jumps but it broke apart for almost 12 hours.
> Any advices how to make them all behave and be closer to each other?

Shorter poll intervals? What is you poll interval?
Also, the system will take a while to realise that clock had moved away.
The slew rate is slowly changed ( too fast and the system would jump
around badly and could become unstable) so the  will slowly increase the
slew rate once the offset starts climbing. 

> Thanks,
> Igor.



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