I'm new to ntp, but have been asked to debug an issue with our NTP configuration. First, here is our setup. We have two processors which each have a third party application reading time off a serial line from two different sources and then disciplining the internal clock on each processor with the "adjtime" system call. xntpd runs on each of these processors with only internal time as a source. One processor is fudged at stratum 0 and the other at stratum 2. Currently, xntp is configured with "enable pll". My first change will be to change "enable pll" to "diable pll" as I believe that we shouldn't have two different applications(our third party app and xntp) discipling the internal clock at the same time.
These two processors act as the NTP servers to all other processors on our network. I've read here that having two servers is a bad situation and that it is better to have four, but that just about anything(including just 1) is better than having two. I believe we our finding that out first hand, so I work to resolve that as well. When I checked the ntp logs for some client processors on our network, I see that occasionaly there are large(upto 1 second) differences between our two servers. On top of this, the clients can not decide which one to sync with and we get stuck in a loop as follows. restart min polling step time/sync to server1 at stratum 0 restart min polling due to step step time/sync to server2 at stratum 2 This exact sequence repeats over and over on appx 5 minute intervals due to the min polling time. I realize that I have many problems here, but I would like to know why ntp toggles between syncing/stepping to server1 and server2 after each polling period. I would have thought that the resultant action would be the same after each polling period. But instead it is consistent that the client steps time to the opposite server that it stepped to last time, like so. 25 Mar 16:36:58 xntpd[7752]: time reset (step) 0.421856 s 25 Mar 16:41:55 xntpd[7752]: synchronized to 192.6.1.21, stratum=1 25 Mar 16:41:54 xntpd[7752]: time reset (step) -0.421930 s 25 Mar 16:46:33 xntpd[7752]: synchronized to 192.6.1.22, stratum=3 25 Mar 16:46:34 xntpd[7752]: time reset (step) 0.419369 s 25 Mar 16:51:31 xntpd[7752]: synchronized to 192.6.1.21, stratum=1 25 Mar 16:51:30 xntpd[7752]: time reset (step) -0.419446 s 25 Mar 16:56:09 xntpd[7752]: synchronized to 192.6.1.22, stratum=3 _______________________________________________ questions mailing list [email protected] https://lists.ntp.isc.org/mailman/listinfo/questions
