nanog mailing list archives

Re: leap second outage


From: Mikael Abrahamsson <swmike () swm pp se>
Date: Wed, 1 Jul 2015 07:38:49 +0200 (CEST)

On Wed, 1 Jul 2015, Jean-Francois Mezei wrote:

However, in systems that expect tightly synchronized clocks, they would want all the nodes to make the NTP adjustement at the same time.

This is both an operating system and application problem.

http://infiniteundo.com/post/25326999628/falsehoods-programmers-believe-about-time
http://infiniteundo.com/post/25509354022/more-falsehoods-programmers-believe-about-time

This is similar to the jiffycounter wrapping, since this doesn't happen that often, it's not commonly tested for. Good way is to start the jiffy counter so it wraps after 10 minutes of uptime. That way you'll run into any bugs quickly. Either we should abolish the leap second or we should make leap second adjustments (back and forth) on a monthly basis to exercise the code.

This is a hard sell though...

--
Mikael Abrahamsson    email: swmike () swm pp se


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