On Wed, Jul 1, 2015, at 08:47, Dag-Erling Smørgrav wrote: > Mark Felder <f...@freebsd.org> writes: > > I'm not an expert on the leapsecond operation, but if I understand it > > correctly there are two ways a system can be notified of a leapsecond: > > via a tzdata update or through NTP. > > Answering a bit late, but no: in practical terms, only NTP works.
Better late than never :-) > Recording leap seconds in tzdata breaks POSIX and a lot of assumptions > in existing code, not only on the day a leap second occurs but at any > time in history after at least one leap second has occurred. > Yeah, I think it's pretty obvious now that doing leapseconds in tzdata is a bad idea -- worse than leapseconds themselves maybe? :-) > > 1) FreeBSD server unaware of leapsecond due to no tzdata entry and not > > synced to NTP ends up 1 second off > > A server which is not synchronized with a reliable external source will > end up a lot more than one second off regardless of leap seconds > because it relies solely on onboard RTCs and oscillators which are both > inaccurate and imprecise. Clock drift will be measured in seconds per > week and vary depending on CPU load, disk I/O, the phase of the moon and > your dog's horoscope. > I was ignoring that bit, but it's worth pointing out to the readers. I should have worded it "...will be one *more* second off" :-) _______________________________________________ freebsd-security@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-security To unsubscribe, send any mail to "freebsd-security-unsubscr...@freebsd.org"
