[ntp:questions] Pool monitoring

Ask Bjørn Hansen ask at develooper.com
Tue Apr 23 19:26:23 UTC 2013


On Thursday, April 4, 2013 2:56:41 PM UTC-7, AlisonW wrote:
> Something which has puzzled me for ages but keep not getting around to asking ...

I don't regularly read this list, so I just saw it now. Pool related questions are mostly better on the pool lists: http://www.pool.ntp.org/en/mailinglists.html (though I think they are welcome here, too, there are just less people to answer them).
 
> My server is allocated for UK and European use only, yet the monitoring is performed from Los Angeles - with the whole continental USA and Atlantic ocean to add transmission delays.
 
I know, it seems crazy!

It turns out not to matter that much though. For the NTP Pool we just need to measure if tens (or more) millisecond accuracy and the distance doesn't make that (significantly) worse. 
 
> Is LA the only monitoring location (ie used no matter where your server is / serves) or can it be reselected to something with the area one seeks to serve?

It's the only monitoring station, currently. The monitoring system compares time with a fancy GPS NTP server and I'm comfortable with the general quality of the network. It's on the roadmap to get more monitoring stations around the world, but the tradeoffs are complicated and I need to beef up the "data processing" infrastructure first to make sure it'll make the service better rather than just different or even worse.
 
> Separately, I note that the same server, on the same physical connection, gets randomly different monitoring times/scores depending on whether IPv4 or (native) IPv6 is used.

Yeah, I see that a lot. The IPv4 and IPv6 internet are surprisingly different.

On my roadmap are tools to help spot these things and see what actionable information we can get out of it.


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