[ntp:questions] NTPD hunts after reboot

Majdi S. Abbas msa at latt.net
Fri Mar 31 18:35:34 UTC 2017

On Fri, Mar 31, 2017 at 01:13:32PM -0400, Charles Elliott wrote:
> 	Some time ago, NTPD used to hunt for several hours after a reboot
> until it settled down to providing good time.  Then it stopped doing that,
> and now it is doing it again.

	Try stopping ntpd, removing the current drift file, and
restarting it.  You might also consider the use of the initial burst
mode option on any configured servers ("iburst.")

> 	In any case, my question now is, if NTPD is no longer resetting the
> computer's battery clock to match its estimate of the current time, would
> that explain why NTPD now indicates a big jump in time after a reboot, hunts
> back and forth within a range of about 30+ milliseconds for about an hour
> after a reboot, and takes about 4 hours before it is providing good time
> again?

	ntpd corrects the kernel's system clock -- not the CMOS RTC.
Each OS makes its own decisions about when to write to the RTC.
Additionally, it's possible the RTC is being managed just fine, but
isn't retaining time of day information because the system's backup
battery is dead.

	If the battery is good, temperature changes post shutdown and 
restart resulting in ntpd not having a good idea of the oscillator's
error is likely.  (Which is why I suggested removing the drift file
on a cold start of ntpd to see if that improves things.)


More information about the questions mailing list