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

osma ahvenlampi oa at iki.fi
Mon Dec 18 16:18:24 UTC 2006


On 12/17/06, John Pilkington <J.Pilk at tesco.net> wrote:
> 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.

Well, I don't know what's really typical, but my FC-based
backend/frontend shuts itself off automatically after recordings,
setting up a timed wakeup 10 minutes ahead of the next one, as much
for saving energy as for silencing it as much as possible. It did
suffer from clock drift once, I don't know exactly why, but over two
years has otherwise kept itself synchronized. This is largely because
it runs NTP with Fedora's standard startup script, which first does a
hard sync with ntpdate, then starts up ntpd to keep the system in
time. Ntpd itself will not correct a drift if it becomes too large,
presumably in order to avoid clock resets caused by time sources gone
bad.

Set up both /etc/ntp.conf as well as /etc/ntp/step-tickers to point to
good time sources to accomplish this.

-- 
Osma Ahvenlampi   <oa at iki.fi>       http://www.fishpool.org


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