[ntp:questions] ntpd stuck at default minpoll on stratum one

Terje Mathisen terje.mathisen at hda.hydro.com
Sat Oct 6 14:30:01 UTC 2007

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.

One possible workaround is to set your prefer peer to another 
local/personal server which uses the Internet to get its timestamps.

- <Terje.Mathisen at hda.hydro.com>
"almost all programming can be viewed as an exercise in caching"

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