[LEAPSECS] internet drafts about zoneinfo (POSIX Time)

[Ask Bjørn Hansen]

On Mar 9, 2011, at 9:00, Warner Losh wrote:


> If you are stratum 1, or slaved to a chain of NTP servers that is 

> properly slaved to a stratum 1 that gets leap seconds right, this is 

> what will happen if your kernel is based on the kernel ntp code from 

> dave mills.


... or if it's a stratum 1 server that's not getting the leap second right, it could be a second off until someone intervenes.


> If you are slaved to an NTP server that doesn't get time right, ntpd 

> will steer out the error in phase by introducing a small error in 

> frequency until the phases are aligned.


... which can take many hours.  It's worth clarifying too that during this time both a second isn't a second long *and* the clock is wrong.  It's like you don't have a cake and you can't eat it.


> If ntp isn't running, then all bets are off.


I'd clarify that as even on systems that are taking care of time much better than average, "all bets are off when a leap second happens".

As you explained, even the optimal best case scenarios are not really good - and in many cases it doesn't work out optimally.

In the field of "making stuff work" it's important that the protocol for any exception or failure scenario is as simple as possible.   Leap seconds sound simple; but they aren't.


 - ask