On 2017-01-02 05:40, Miroslav Lichvar wrote: > On Sat, Dec 31, 2016 at 01:09:46AM -0700, Brian Inglis wrote: >> On 2016-12-30 16:32, Ask Bjørn Hansen wrote: >>>>> restrict 127.0.0.1 >>>>> restrict -6 ::1 >>>>> >>>>> pool 0.pool.ntp.org >> >> Add preempt to pool statements to drop unselected servers and >> acquire new servers to maintain a majority clique - see below. > > Does the preempt option actually do anything in the pool directive? > I thought servers added from pool are always "preemptable".
I think they may be treated as ephemeral associations but require the option to be dropped rather than kept around as falsetickers. >>>> How many servers should the client use at the same time? The >>>> default value of tos maxclock is 10, so it would use 10 servers. >>>> That seems a bit excessive. If it should be equivalent to the >>>> current recommendation, the config would need to include >>>> >>>> tos maxclock 4 >> >> Keep it odd - tos maxclock 5 - for sync, majority clique requires >> truechimers *>* falsetickers - truechimers == falsetickers is >> *unsynced* - 5 allows 2 servers "off" in some way at the same time >> (e.g. during weekend maintenance windows when servers often drop >> out - YMMV) see http://doc.ntp.org/current-stable/select.html . > > Is it common to get two falsetickers at the same time? Not common, but it happens fairly regularly, mainly weekends, especially long weekends, when maintenance seems to get done and servers become unavailable for a few hours or days; and any time there is a major network issue, as when there were problems with US West across the NW US, and during DDoS attacks. Sometimes a source just goes off the rails, so it's good to have a buffer against another source dropping out, while looking around for an good alternative source. -- Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
