On Tue, Dec 27, 2011 at 21:53, Terje Mathisen wrote: > Not for just 4 or 6, but if you have a lot and configure them with 'preempt' > then you will end up with a smaller active set, consisting of (mostly) > better servers, right?
I haven't experimented with preempt, but I believe you're right as long as more than "tos maxclock" (default 10) are configured. However, that winnowing will be a startup process with a static result over each run of ntpd once enough preempt peers are discarded -- so if one of the 'winners' later goes offline, it will not be replaced to get back to maxclock sources. > However, even without this feature, simply listing all 6/8 servers, from > both ends of the country, will normally result in ntpd figuring out which > servers are better, and then dropping the rest very quickly back to poll > 1024. > > I.e. geographic load balancing without having to setup different ntp.conf > files for each group of clients. ntpd provides two other capabilities supporting common client configuration. manycast uses multicast solicitation by clients to automatically spin up maxclock associations, and can be used in client/server or mesh configurations. The associations thus started are preemptible and unicast client/server after discovery. Starting in ntpd 4.2.7, "pool" associations are implemented in the same way as maycastclient except the discovery of potential servers starts with a DNS round robin name, which could be in your DNS or (for example) pool.ntp.org, rather than with a multicast IP group address listened to by manycast servers. The earlier ntpd implementation of "pool" was a startup-only process of spinning up to the lesser of maxclock or the number of addresses received in the round robin response to the one-time DNS lookup at startup, so it also would not replace servers over time. Cheers, Dave Hart _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
