[ntp:questions] ntpd stuck at default minpoll on stratum one
Per Hedeland
per at hedeland.org
Sat Oct 6 18:50:54 UTC 2007
In article <hoikt4-f6p.ln1 at osl016lin.hda.hydro.com> Terje Mathisen
<terje.mathisen at hda.hydro.com> writes:
>Dennis Hilberg, Jr. wrote:
>> Hi,
>>
>> I have a stratum one server running ntpd 4.2.4p3 at 1.1502 with a Garmin
>> GPS 18 LVC as a refclock. I use the shmpps driver from
>> http://time.qnan.org/ . Since this driver only provides the PPS signal,
>> I need to have a few other servers defined in my ntp.conf so that my
>> ntpd knows what time it is.
>>
>> Here's my concern: the poll interval on those servers is always stuck at
>> the default minpoll (64sec), even though I have not specified so. I
>> would rather not poll those servers at such a rapid rate, but ntpd seems
>> to be doing this on its own, as far as I know.
>
>I think this is a known problem/bug/feature: The prefer peer responsible
>for naming the PPS ticks is clamped at minpoll. In fact, if you adjust
>minpoll to 4 (i.e. 16 seconds), which can be a good idea for a GPS-class
>PPS signal, then you'll also lock your prefer peer at the same rate.
AFAIK it's not limited to the prefer peer - note that Dennis' ntp.conf
didn't have 'prefer' on *any* of the remote servers, I believe having
one used to be a requirement for a PPS-only clock to work, but
apparently that has changed. I.e. if you have a reference clock, *all*
remote servers will be clamped at minpoll for the reference clock.
--Per Hedeland
per at hedeland.org
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