[lug] Time Warp

Hugh Brown hugh at math.byu.edu
Tue Feb 21 15:36:07 MST 2006



On Tue, 21 Feb 2006, Michael Belanger wrote:

> On Tuesday 21 February 2006 14:19, Gordon Golding wrote:
> > I have a server that every once in a while, changes it's time - maybe once
> > a week?  I look at it and it's fine for a few days and then at 13:31 the
> > date says it's 7:31.  (6 hours...?)  I thought there might be some script
> > doing it, but I checked crontab for all the added users and root and there
> > is nothing there.
> >
> > I have a little script running now to grab 'date' regularly, so I can see
> > when it happens.
> >
> > I'm in the correct timezone; Denver, not using NTP.
> >
> > Any thoughts?
>
> CMOS Battery.. Replace it.
>
> Regards,
>
> Michael
>


I was about to second the opinion that the hardware was at issue.  But
Denver is GMT-6 (during MDT which could mean that something was causing
the clock to reset to GMT).  But then I thought that "it is MST right now
so its GMT-7, so much for that theory."

I'd have my script do something like:

hwclock --debug --show

and compare it with output from date.

The last time I had weird clock issues, it turned out to be the kernel not
getting along with a motherboard and the hwclock would count for 3 seconds
and then start over.

I'd also look to make sure that nothing is modifying /etc/localtime as
well.

The easy way to check the CMOS battery is to power off, unplug the
machine, wait for a minute, and power back on.  If the date resets, you've
got a bad battery.

Hugh



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