Re: Mac mini: serious clock drift
On Thu, Mar 08, 2007 at 06:08:57PM -0500, Rick Thomas wrote:
> On Mar 8, 2007, at 10:04 AM, Bram Senders wrote:
> >I am having issues with clock drift on my G4 Mac mini. The clock
> >drifts so much that even ntpd can't keep up with it. I keep getting
> >messages like "time reset +2.404131 s" from ntpd approximately every
> >15 to 20 minutes.
>
> I've got two minis running Debian Etch. Both of them have this
> problem. It seems to be a firmware problem. But it's fixable.
>
> Attached is a tar file you can untar from root. It will put a script
> called "tickadj" into /etc/init.d with a parameter file in /etc/
> default/ and a pointer to the script in /etc/rcS.d .
Ah, I didn't know about the "tickadj" command. All your script does is
call the tickadj command included in the ntp package with the configured
value, right?
> The parameter value in the tar file works OK on both of my minis.
> You may have to adjust it for your particular situation.
I had a look at the adjtimex package mentioned by Badger, which tries to
find out the best value to set the kernel tick variable to, and this
comes up with the same value that you provided with your tickadj script,
namely 10029. So I used this value, and my clock runs much better now!
After a couple of hours of running like this, ntpd hasn't done a single
"time reset", and my offset to the time server is only something like 15
milliseconds, where before it would quickly become thousands of
milliseconds.
I'm going to let it run like this for a few days, to see whether it is a
stable solution. Anyway, thanks for the hint!
Bram
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