ntp polling interval

[larry-au]

I there a way to change the ntp "polling interval", so that the time synchronisation interval is longer than the default?

[lilsense]

now, why would you want to play with that?

[larry-au]

Well, time sync updates are in the order of >5 in a 20 minute period. That would be one significant reason.
On a Linux server, I would be setting that to no more than four times a day, with the minimum and maximum poll intervals. As OPNsense is not using the usual ntp.conf -or- chrony.conf configuration files, I venture to ask what is the 'best practice' method on OPNsense/FreeBSD?

[Patrick M. Hausen]

Why would you want to sync only four times a day? The closer your local time is to the reference time source the better. Not that it would cause much traffic ...

The defaults are more frequent because VMs and systems with "quirky" time keeping hardware tend to drift much faster.

[lilsense]

It's not just VM's but any processor is prone to shifts and I am not sure 4 times a day solves any problems other than maybe being a half a sec behind, possibly.

[larry-au]

Well, should have been a simple two or three post enquiry! And with all due respect; rather than a pub table discussion about other peoples experiences and opinions in different scenarios.
Plenty of papers around about offset time drift in peer host synchronization, in IEEE and ACM, etc. But that doesn't solve/answer the original question.
So, in the absence of a definitive response, I'll have to git clone the repository and dig through the code.  ::)
Somewhat disappointing for what I would have expected to be a professional and collaborative forum.
:(

[lilsense]

instead of the issue you are discussing tha has to with the two time servers, you'd be best just either used one or very many. But then again, have at it and do as you please... :D

[Patrick M. Hausen]

Somewhat disappointing for what I would have expected to be a professional and collaborative forum.

My collaborative and professional recommendation based on 30 years experience of data centre operation: activate ntpd and let it run as the developers intended. This piece of software is auto tuning with an adaptive interval and supposed to do the right thing. I don't see any reason why one would want to mess with the timing parameters.

Kind regards,
Patrick

[eicastic1]

To the OP....it's not adjustable. NTP is a protocol with an algorithm baked in (NTPd is the service). You may be thinking of SNTP (simple network time protocol) which you can adjust the interval on, but that's far less accurate.

A properly running (full) NTP client will decide on its own how often to poll the servers you've configured. Initially it will check every 64 seconds, but once the clock has been stabilized, the polling may be every 1024s.

If the algorithm detects something wonky with the clock it will automatically start polling more often as needed.

The full NTP algorithm can get into the millisecond area on a WAN, and even more accurate on LANs.