I monitor many NTP servers and have observed off-by-N second errors (N often 1, 2, 3) for years. Some of these errors are understood: fuzzing errors in ntpd, late NMEA arrival times. But many of these errors have unknown causes. These errors can recur on a given server with the same offset. On May 22 I noticed a system running ntpsec + GPSD ( khronos.mikieboy.net,) was in error by two seconds. The same system was also off by two seconds on January 15. I asked about this on the ntpsec mailing list, which happens to include several GPSD folks. Their answer was that a GPSD error caused the problem, but was fixed in GPSD 2.0 No bug description seems to exist, so I'm uncertain whether the errors I saw were related.
The off by N-second errors are often seen soon after NTP server initialization. I lack detailed configuration information for many of the affected systems, unfortunately. On Mon, Jun 8, 2020 at 5:02 AM Miroslav Lichvar <mlich...@redhat.com> wrote: > On 2020-06-08, a...@avtodoria.ru <a...@avtodoria.ru> wrote: > > понедельник, 8 июня 2020 г., 10:52:36 UTC+3 пользователь Miroslav > > Lichvar написал: > >> If you need something to report a large offset to ntpd via SHM, you > >> could try this program for testing leap seconds: > >> > >> https://github.com/mlichvar/leapshm > > > Thank you ver much. Please can you explain the params program uses. > > Second can be path to unix socket or something else starting not with > > "/" to use SHM. What about third param ? > > It's the number of seconds before the hardcoded leap second time (1 Jul > 2015 00:00:00 UTC) where the time fed by the program should start. E.g. > if it was 600, it would start 10 minutes before the midnight of the leap > second. You would probably want to start with a larger number (if you > don't want to test a leap second) and also change the LEAP_TIME constant > to a current date. > > -- > Miroslav Lichvar > > _______________________________________________ > questions mailing list > questions@lists.ntp.org > http://lists.ntp.org/listinfo/questions > _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
