Re: [chrony-users] source that exceeds maxdistance causing some odd issues

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On Tue, May 14, 2019 at 10:37:06AM -0400, Dan Arena wrote:
> This specifically says "only valid measurements from synchronised
> sources", but It was still showing log lines for the source.

Measurements that passed the NTP tests 1-7 are considered valid. A
root dispersion of 5.4 seconds is still ok at the NTP level. It's only
later in the source selection when that's too much.

> When I
> looked at `chrony sources -v` it listed the source state as "?", which
> is quite confusing because the source is not actually "unreachable". 

Yeah, the -v help is confusing here. '?' is a catch-all symbol for all
other problems. The man page says "or whose packets do not pass all
tests", but that still is not an accurate description.

> Why does chrony show the source as " '?' = unreachable", instead of
> like "'x' = time may be in error"? 

x indicates a falseticker. Large dispersion is something very

Ideally failures in the selection tests, and there are quite a few of
them, would all have different symbols. I hesitate with that as it
might break compatibility with tools parsing the chronyc output.

> Why are there lines in the
> measurements file when the source is not synchronised?

The source is synchronized, but it's not considered good enough to be
used for synchronization of the local clock.

> Should I just leave the maxdistance at 16.0?

Yes, if you can't get access to a better server.

> I am kind of inclined to
> blame the person managing the NTP server; they should probably sync
> its time regularly some how, either manually or from an external
> source (over internet or GPS, whatever).

It's probably a Windows NTP server. Large dispersion seems to be a
common problem with them. The admin might want to configure a shorter
polling interval or switch to ntpd.

Miroslav Lichvar

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