[ntp:questions] Wrong time after changing hardware

Tom Smith smith at cag.zko.hp.com
Fri Jul 20 20:52:02 UTC 2007

Marc Muehlfeld wrote:
> Hello,
> I'm running a NTP server on one of my Linux servers that distribute time 
> in our local network. But since I changed Mainboard/CPU/RAM on that 
> machine, the machine is allways having a time in future.
> When I restart the NTP service, the time is sycronized again. But 
> allready after 12h there is a drift difference of about +6 seconds. 
> Meanwhile I reinstalled the service, but that didn't made any changes. 
> Before switching to the new hardware, it run fine for about 1.5 years.
> Any idea?
> The server is running Suse 10.0 with xntp 4.2.0a.
> Regards
> Marc

Hello Marc.

I'm surprised nobody has described the obvious yet.

You changed the oscillator, so the system has a different characteristic
frequency error than your previous hardware. However, you are, I assume,
using the same filesystem, including the previous /etc/ntp.drift (or
wherever you drift file is stored) that contains the frequency error of
your previous hardware.

1) Stop (x)ntpd
2) Delete your existing ntp.drift file (the path should be shown in
    your ntp.conf)
3) Run "ntpdate -b [a reliable server]"
4) Start (x)ntpd

This will re-initiliaze the drift rate for your new hardware. Give it
a day or 2 to settle without stopping (x)ntpd. If you still have
a problem at that point, you may have some other hardware-related
issue, but that's the first step.


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