[ntp:questions] Change poll interval at runtime?

A C agcarver+ntp at acarver.net
Sat Feb 25 22:05:48 UTC 2012

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 associated
>>> 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 accurately.

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.

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