[mythtv-users] Offset all recordings by a few minutes

John Pilkington J.Pilk at tesco.net
Sun Dec 17 07:58:56 UTC 2006

Michael T. Dean wrote:
> On 12/15/2006 04:51 AM, Phill Edwards wrote:
>>> I found that although I had ntp enabled my clock was still off by
>>> minutes.  It appeared that my system clock was chasing its own tail.
>>> The ntp literature seemed exhaustive but not written for the user.
>>> ntpd -q   , run occasionally, seems to work.
>> Or, even easier, use ntpdate:
>> # /usr/sbin/ntpdate -u -s time.optusnet.com.au
> Or, rather than fixing the symptom, fix the problem...
> 1) Shut down ntpd on the host that's not working.
> 2) rm /etc/ntp.drift (or whatever you've specified as your driftfile in 
> /etc/ntp.conf or where ever you've put your NTP configuration file--i.e. 
> your drift file may be in /etc/ntp/ or something)
> 3) rm /etc/adjtime or /var/lib/hwclock/adjtime or wherever you keep it
> 4) run "ntpdate -b 0.pool.ntp.org" (or use a hostname like 
> "0.us.pool.ntp.org" to get a server close to your location)
> 5) run "hwclock --systohc" and make sure you specify the "--utc" 
> argument if your hwclock should be set to UTC (without adjtime, the 
> previous default is gone)
> 6) start ntpd and let the system start over from scratch in its 
> calculation of system drift
> 7) see http://tldp.org/HOWTO/Clock.html and, especially, "
> 2.2 Potential Conflicts" ( http://tldp.org/HOWTO/Clock-2.html#ss2.2 ), 
> which may explain how your system got "broken" in the first place 
> (allowing you to fix the /source/ of the problem, as well as fixing the 
> problem)
> Mike

Mike: Thanks for this helpful reference.  I was the one who posted the 
report about my experience with ntp, which was, as far as I remember, in 
the FC5 out-of-the-box configuration.

I don't run the system (a single box) continuously - which seems to be 
part of the problem, and probably isn't typical of MythTV users - and 
while the time offset gradually built up I was still under the 
impression that ntp was doing what I wanted.  It wasn't.  I don't think 
it connected in the expected manner to any external reference, and I got 
the impression that it fell back to tail-chasing mode.


More information about the mythtv-users mailing list