[ntp:questions] NTP not syncing

unruh unruh at invalid.ca
Sat Dec 7 23:22:58 UTC 2013


On 2013-12-07, Harlan Stenn <stenn at ntp.org> wrote:
> unruh writes:
>> As I said, get chrony if you want much faster convergence, if you want
>> better control of the time offset from UTC, and if yourun Linux or
>> BSD.
>
> And this begs the question of "faster convergence towards *what*?"

UTC :-)

>
> NTP looks a a number of time sources, finds a majority clique that
> exhibit "good" (consistent with respect to each other, as observed by
> the local system) behavior, and steers the clock towards that time.

So does chrony, except that it takes one of those (the one with the
smallest spread I believe) as the representative.
>
> As I understand it, chrony steers the local clock towards the master
> time source it is following.
And it figures out which source it is following by looking at all of the
sources it is following.

>
> Assuming this is all true (or true enough), there are times and
> situations where one of these approaches is better than the other, and
> other times and situations where the converse is true.

Yes, but tests that both I and Lichvar have run show that chrony follows
to much higher accuracy than does ntpd.
>
> H



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