[ntp:questions] Change poll interval at runtime?
Ron Frazier (NTP)
timekeepingntplist at c3energy.com
Sun Feb 26 05:55:12 UTC 2012
On 2/25/2012 5:05 PM, A C wrote:
> On 2/25/2012 13:09, Richard B. Gilbert wrote:
>> On 2/25/2012 1:20 AM, A C wrote:
>>> On 2/24/2012 21:26, A C wrote:
>>>> Is it possible to change the polling interval of one or more
>>>> servers at runtime? It seems like I should be able to run:
>>>> ntpq -c "writevar &associd hpoll=N" or is it ppoll?
>>> Actually, I should have been more specific and say change the minimum
>>> polling interval. In other words, be able to adjust the conf file's
>>> minpoll flag at runtime instead of restarting.
>> What problem are you trying to solve?
>> NTPD does a pretty good job of adjusting itself most of the time.
>> Short poll intervals are useful when correcting large errors.
>> Long poll intervals allow NTPD to make small corrections very
> The idea was to bump up the minimum poll interval after ntpd has been
> running for a day or so to something more kind to the remote servers
> because the refclock is holding the remote servers clamped to 64
> seconds. If I set minpoll in the config file, then ntpd's start up
> takes a long time because of a long poll interval. If I don't set the
> minpoll, then ntpd doesn't do "a pretty good job" because it clamps
> the polling interval.
I've noticed the same thing. You could try what I'm doing, although I'm
still testing for the best configuration.
# GPS Lines
server 127.127.20.5 prefer minpoll 3 maxpoll 6 mode 72
fudge 127.127.20.5 time2 0.3100 refid GPS1
# Internet server lines
# NIST New York
server nist1-ny.ustiming.org minpoll 8 maxpoll 13
# other internet server lines similar
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timekeepingdude AT c3energy.com
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