ntp problems stratum 2 to 14?

[Bob Bishop]

Hi,

> On 5 Mar 2020, at 06:33, Peter Jeremy <peter at rulingia.com> wrote:
> 
> Hi Dewayne,
> 
> Sorry for the delay.  Unfortunately, I can't really suggest anything -
> it's not clear to me why ntpd would prefer a stratum 14 clock over a
> stratum 2 clock.  Have you tried looking through the debugging hints
> page (https://www.eecis.udel.edu/~mills/ntp/html/debug.html)?
> 
> I haven't seen that problem but I don't use the local clock.
> 
> During startup, it would not seem unreasonable for the local clock to
> become valid first because it will have a lower jitter.  But ntpd
> should switch to the stratum 2 clock and stay with in as the better
> time source.  One problem is that if ntpd decides to switch away from
> the clock for any reason (eg a burst of jitter), it may get stuck on
> the local clock as it drifts further from "real" time.

Yes. I’ve had exactly that happen with a stratum 1 (GPS) server with only local as fallback. The GPS signal dropped for a while and the box drifted off sufficiently that it wouldn’t reacquire the accurate clock.

The solution is to add a few pool (or whatever) servers into the config - you can still ‘prefer’ a local server but it ensures the box won’t drift off into the weeds.

> --
> Peter Jeremy

--
Bob Bishop
rb at gid.co.uk




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