| Re: [chrony-users] reachability cycling between 377 to 000 |
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- To: chrony-users@xxxxxxxxxxxxxxxxxxxx
- Subject: Re: [chrony-users] reachability cycling between 377 to 000
- From: Miroslav Lichvar <mlichvar@xxxxxxxxxx>
- Date: Tue, 20 Oct 2020 09:01:43 +0200
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On Mon, Oct 19, 2020 at 05:42:17PM -0700, wis1@xxxxxxxxxxx wrote:
> When I changed "chrony.conf" to include
>
> refclock SHM 1 poll 3 refid PPS lock GPS
>
> Restarting 'chronyd' with this gives a solid 377 all the time (where "all
> the time" is defined as "> 60 min and I got bored"). I'm now seeing:
That might be a fluke. From the sources data it looks like the offset
of your "GPS" source sometimes jumps from about 0.15 to 0.63. That's
too much for the PPS refclock to lock reliably. The gpsd-users list
would be a better place to ask for help with that.
> pool pool.ntp.org iburst
> refclock SHM 0 poll 3 refid GPS
The SHM source should have the noselect option and it should also have
it's offset and maximum error set, e.g. offset 0.15 delay 0.2.
> refclock PPS /dev/pps0 refid PPS lock GPS
If you can't fix the GPS source, you would need to consider dropping
it and just rely on the NTP servers to provide the initial sync for
the PPS.
--
Miroslav Lichvar
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