Hi, This probably isn't the place to post this, if so, I will apologise in advance..
I have a problem that really baffles me, having run ntp servers for years. I have two ntp servers set up in the local network, from which another 40 odd servers synchronise. Some of the servers do function as expected, and keep time quite accurately, however, the majority of servers rapport an error that I cannot lock down, and it's currently baffling me... (It's probably something obvious I'm overlooking or so I hope). The logs on the systems that have problems usually show the following pattern Sep 7 17:43:48 sn ntpd[11721]: synchronized to 10.7.100.28, stratum 2 Sep 7 17:57:51 sn ntpd[11721]: time reset +71.784598 s Sep 7 17:59:10 sn ntpd[11721]: synchronized to 10.7.100.27, stratum 2 Sep 8 05:29:11 sn ntpd[11721]: no servers reachable Sep 8 05:34:37 sn ntpd[11721]: synchronized to 10.7.100.28, stratum 2 Sep 8 05:35:52 sn ntpd[11721]: time reset +74.977115 s Sep 8 05:36:41 sn ntpd[11721]: synchronized to 10.7.100.28, stratum 2 It appears to have an issue nearly exactly every 12 hours, the time difference is getting worse, it started at around 1-2 seconds, and has steadily increased, and how deviate with 74 seconds. One day I was watching the event, and saw the machine go from being +/- 4 ms out to suddenly becoming +/- 36000+ out, so it appears to be something specific that causes the problem. The strange thing is that the servers appear to be fully synchronised for most of that time, but suddenly the jitter increases dramatically, and the clocks offset change to something very large, and then is reset by ntp a few cycles later - I've decreased the poll times to be maximum of 256 seconds, as that seems to correct the problem faster. The configuration of all servers (ntp.conf) is restrict default nomodify notrap noquery restrict 127.0.0.1 server ntp1.i.tv2.dk minpoll 1 maxpoll 8 iburst server ntp2.i.tv2.dk minpoll 1 maxpoll 8 iburst server ntp.i.tv2.dk iburst tinker huffpuff 7200 driftfile /var/lib/ntp/drift broadcastdelay 0.008 keys /etc/ntp/keys The versions of ntp that's in use, varies a lot with the machine ages, operating systems, and so forth, strangely enough it seems that most machines have the same problem. Similiarly the systems are running suse, rh 4/5, on different kernel versions. My initial instinct was that it might have been network related. NB: the tinker huffpuff 7200 was something that was added to see if it had any effect or not, minpoll, maxpoll values were added as they seem to improve recovery from the problem, however it's treating the symptom. As far as I've ascertained, the ntp servers are at no time unreachable, and do not appear to ever loose sync with their clock sources. Their logs indicate that the occasionally - ever hour or so, that they do change between different time servers. Any ideas are most welcome. _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
