NTP?

[Greg Lindahl]

> The only negative side I've ever seen to it is that it used to die
> without much of a complaint if it ran into trouble, and one form of
> trouble it would run into was that would fail if the clock was offset by
> too large an interval from the time it was trying to set.

Yeah, this is the fundamental annoyance with NTP. So to use it well:

1) Your boot script needs to run ntpdate before starting ntpd, so
   that your clock gets jumped. The standard rpm has that now,
   although you should reconsider the timeout number.
2) You need to make sure your hardware clock gets set to be
   correct reasonably frequently, because...
3) It can still screw up if all your time servers are down when the
   system boots. If the hw clock is too far off, ntpdate times out
   and then ntpd fails to do its job.

Grrrr.

One plus, though, is that PBS will keep a node down if the clock is
too far off. But you might not notice for a while.

Now if you want GOOD time synchronization (to within a microsecond)
that's a *much* harder problem...

g