On Thu, May 26, 2011 at 09:49:55AM -0700, Chuck Swiger wrote: > On May 26, 2011, at 9:28 AM, Florin Andrei wrote: > > On 05/23/2011 03:57 PM, Chuck Swiger wrote: > >> > >> That being said, it's not expected that the preferred time source > >> would change that frequently. You'd probably do better to run > >> with at least 4 servers, so that it can better judge their > >> reliability; with only two, there isn't much basis for > >> comparison. > > > > So, basically you're saying the "quality" of the NTP servers > > fluctuates for some reason and this machine is flipping back and > > forth between them? > > Evidently yes for your case. With only two servers, it may not be > possible to find a best intersection via ntpd's variant of > Marzullo's algorithm:
I think the frequent source switching can happen with any number of sources if the two best servers have similar synchronization distance. With more servers you may have a better chance that the best server is significantly better than the others though. The problem can be usually fixed by increasing the anti-clockhopping distance by "tos mindist", perhaps to 10 ms. -- Miroslav Lichvar _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions