[mythtv-users] System Time runs fast for some reason

[chris at cpr.homelinux.net]

On Sun, Aug 27, 2006 at 07:02:15PM -0600, Greg Schade wrote:
> On Sun, 2006-08-27 at 19:56 -0400, Jon Kunze wrote:
> > Everything is running great using .19.1, but for some reason the
> > system clock seems to be running a bit fast.

> went through the same problem myself for a while.  use "adjtimex"
> http://linux.togaware.com/survivor/Using_adjtimex.html
> then I added the command to the end of /etc/rc.d/rc.local allowing it to
> adjust the clock at boot up
> and I wrote a really simple script using "ntpdate" to check a time
> server and put it in /etc/cron.hourly I named it sync-clock

If you're using ntpd you shouldn't need to use adjtimex as the 
daemon (if running properly) will automatically adjust your clock 
on a continual basis.  In fact, the adjtimex page you referenced 
specifically reccommends using ntpd instead of adjtimex.

It's possible to run ntpd and ntpdate on the same system, but 
ntpdate won't do anything if ntpd is already running.  When they 
are both installed it's more typical to call ntpdate *once* when 
the machine boots (before starting ntpd) and then launch ntpd when 
the clock is already close.  That allows you to specify 
conservative adjustment limits to ntpd while allowing ntpdate to 
make big changes when the machine first boots.  If your time source 
is stable it's easier to just give ntpd permission to make the 
large changes itself.

If you're going to use ntpdate instead of ntpd then you really 
don't need a script - it's designed to be runnable directly from 
the crontab.