Re: How to disable "make[1]: Warning: File `somefile' has modification time 53 s in the future"?

[Bob Proulx]

Peng Yu wrote:
> A side question. How to set two systems to have coherent time? Right
> now, I have two systems that synchronize with a public time server
> every day. But as you see their time is off for some reason. I guess
> the only option to synchronize one machine to another, rather than
> both synchronize to a public time server.

When I read "synchronize with a public time server every day" it
triggers an alarm in my head.  This almost never has good results.
Stepping the clock has many undesirable problems.  Instead of stepping
the clock it is better to keep the clock continuously in sync.  That
avoids clock steps and avoids the problem you are seeing right now.

NTP is the standard network time protocol.  Personally I like ntpd for
maintaining system time synchronization although there are other
alternative programs too.  They work by adjusting the time of a clock
second, either shortening or lengthening, so that every second is seen
with no steps but the time is not allowed to drift away from the
upstream time source.

Your clock seems to be very fast indeed to get 50s ahead within a day.
That is not good.  And not normal.  Something seems very wrong (such
as already having some type of clock control program actively
misbehaving) in order for it to be that far away.  I would look for a
problem there first.  Because, if present, that will interact
negatively with any other time synchronization processes that is added
to correct for it.

You didn't say what type of system is hosting your filesystem so I
will just make an advertising suggestion.  :-) If your system were
Debian then you could 'sudo apt-get install ntp' and pretty much be
solved of this problem.  Do not forget to remove any other cron-based
time stepping processes or it will really confuse things.  Two or more
programs trying to fight over the clock is not good.

Bob