I just posted a request for help testing an improvement to ntpd to automatically refine the set of pool servers being used. Rather than repeat myself, I'm going to quote it below. Please forgive my laziness.
https://community.ntppool.org/t/testing-needed-for-ntpd-pool-change-to-whittle-outliers/2874 ntpd has had support for over a decade generally described as “automatic server discovery” that was designed to not only select servers automatically, but also refine the selection over time to stick with servers that contribute to the time solution and preempt and replace outliers. This code is used both for manycastclient and for pool associations. Unfortunately, for over a decade it’s been effectively inoperative except in the rare situation where less than tos minclock (default 3) servers survive the clock clustering and selection process. After a bunch of testing myself, I’d appreciate others willing to donate some time to try out the new code and help work out any remaining kinks. Obviously pool clients using ntpd are prime candidates to test this. Those running ntpd as pool servers could also help out by configuring pool associations with noselect or using prefer on their explicitly configured sources. The basic logic is that when a server has not survived for 10 consecutive poll intervals it is a candidate to be preempted. Only the lowest-scoring servers are removed, and only once there are already maxclock associations. Those preempted are automatically replaced within a poll interval or two by newly-solicited sources. You may want to adjust tos maxclock from its default of 10 to see how it works combining more or less sources. The code is available in: *https://people.nwtime.org/hart/ntp-dev-3792-msm.tar.gz <https://people.nwtime.org/hart/ntp-dev-3792-msm.tar.gz>* One concern to watch out for is the possibility of increased queries to the pool.ntp.org DNS servers. That effect fades as the client settles on a set of sources which all survive and potentially contribute to the time solution. Feedback here or to h...@ntp.org or questions@lists.ntp.org is most welcome, even if only to say you’ve tried it and didn’t have any issues, so I get a feel for how much testing has been done. Thanks in advance! Dave Hart P.S. To those seeinig this on the comp.protocols.time.ntp newsgroup, if you like you can subscribe to the linked mailing list by sending any email to questions+subscribe at lists.ntp.org
