On Sun, Jul 1, 2012 at 09:08 UTC, David J Taylor wrote: > - The Windows PCs fed from either Garmin GPS 18/x LVC or Sure Electronics > GPS boards appear to have reset some 17..24 minutes after 00:00, suggesting > they were using the GPS for the time (as well as the precise edge), and the > GPS devices took some time to reflect the leap-second in their serial > outputs. Perhaps it would have been better had they not believed the GPS > serial time, but that coming from other servers? The reset resulted in a > further period of about an hour until full accuracy was restored. ntpd > 4.2.7p285
Your offset graphs tell a slightly more nuanced picture which fits my expectations. ntpd slewed the clock 1s back over 2s near midnight UTC as expected, regardless of what its sources told it, because it knew the leap second was scheduled then. Your logs should show an entry noting the insertion. Then the GPS-connected sources immediately showed a +1s offset, and due to the short polling interval and the lag before the GPS receiver got its head straight, managed to slew away much that 1s offset. It seems like with cheap GPS receivers, a longer polling interval might be wise around leap seconds. Or switching to internet sources to number the seconds while keeping PPS... > - The Windows PCs working from LAN/WAN sources saw no glitch. ntpd > 4.2.7p285 > > Offset graphs: > > http://www.satsignal.eu/mrtg/performance_ntp.php Cheers, Dave Hart _______________________________________________ pool mailing list [email protected] http://lists.ntp.org/listinfo/pool
