[ntp:questions] once 'ntpd' stops, does the drift file value continue to get used for clock adjustments?

Richard B. Gilbert rgilbert88 at comcast.net
Thu Mar 17 22:44:17 UTC 2011

On 3/17/2011 6:09 PM, Gautam Thaker wrote:
> I have a stable drift value on my fedora 12 node and everything is
> running well. (offsets are well below 1msec). If I now stop 'ntpd'
> will my time start to drift relative to the 'correct time' by the PPM
> value in the drift file? Or is it that ntpd has already set things up
> so that corrections as per last value of drift file will continue
> indefinitely? If it is the latter and if indeed my drift value is
> quite good (as ntpd had run for many days already), it seems I can go
> for many more days w/o ntpd and not get very much out of sync at all.
> Any comments welcome. Thanks.
> Gautam

What problem are you trying to solve??

The only way to be certain is to test it!  I suspect that much depends 
on the temperature and load on the machine.  If both are constant it may 
take a long time for the time drift noticeably.

If you really need the time to stay within, say, 100 microseconds then 
forget your scheming and just make sure that NTPD is running 24x7!

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