On 9/20/05, Mark Knecht <[EMAIL PROTECTED]> wrote:
Yes. After changing the mythfilldatabase window, I waited until two
days had passed. During those two days, the system did its normal
shutdown-and-wakeup thing. That is, it shutdown the computer and
re-booted at the times when programs were scheduled to be recorded.
Yeah, that's what I thought ! How could the I/O system of newly-built
computer be unable to keep up with only two write-to-disk tasks. I've
watched the disk-activity light (not a good measure of load, I know),
and it blinks slowly. It's nothing like when the system is running updatedb
or makewhatis.
If there is a problem with starting a second recording when a first recording
is underway, then it should be repeatable. I may set up some tests that
run during Daytime TV, to see if I can get the out-of-sync problem to
repeat, reliably.
--
MM
On 9/20/05, Mercury Morris <[EMAIL PROTECTED]> wrote:
> On 9/19/05, Michael T. Dean <[EMAIL PROTECTED] > wrote:
> > Could this be a problem with your system (instead of a problem with
> > Myth) that others are seeing where running mythfilldatabase (or wget of
> > any kind) while recording causes an IOBOUND situation that prevents
> > information from being written properly and causes an A/V sync offset?
> > In other words, does Charlie Rose happen to record around the time your
> > mythfilldatabase runs?
> >
> >
> http://www.gossamer-threads.com/lists/mythtv/commits/150176
>
> Yes Mike ! In the mythbackend.log, there are IOBOUND entries that
> correspond in time exactly! to the discontinuities in the Charlie Rose
> show.
>
> But here's the thing: I had already suspected mythfilldatabase because
> it had been running within the Charlie Rose hour. So, I changed the
> window for mythfilldatabase to run outside of that hour - problem still
> occurred.
Did you completely restart the backend mysql processes after doing
this? Maybe even reboot to be sure?
Yes. After changing the mythfilldatabase window, I waited until two
days had passed. During those two days, the system did its normal
shutdown-and-wakeup thing. That is, it shutdown the computer and
re-booted at the times when programs were scheduled to be recorded.
>
> So, mythfilldatabase is not the cause, BUT the system is recording
> Letterman (in HDTV) from an HD3000 card at the same time.
> I guess that the simultaneous recordings are too much for the I/O
> system to handle - a bit of a surprise to me.
Not likely unless you have no DMA on your hard drives or the data is
traversing the network. My backend storage is not on my backend
server. I never see problems like this but I don't record HD either.
None the less that should be less than 5MB/S which even a non-DMA hard
drive might keep up with...
Yeah, that's what I thought ! How could the I/O system of newly-built
computer be unable to keep up with only two write-to-disk tasks. I've
watched the disk-activity light (not a good measure of load, I know),
and it blinks slowly. It's nothing like when the system is running updatedb
or makewhatis.
>
> But now, thanks to you pointing me to the logs, I can set up the
> recording schedules so that only one recording takes place at a time.
> (Of course, I feel that I should have looked in the logs without having
> to be told to.)
>
> One more observation, about a specific time: Last night's out-of-sync
> break occurred at 36:19 into the Charlie Rose show. That's within the
> first two minutes of Letterman. Maybe there is extra overhead at the start
> of a recording?
Possibly.
If there is a problem with starting a second recording when a first recording
is underway, then it should be repeatable. I may set up some tests that
run during Daytime TV, to see if I can get the out-of-sync problem to
repeat, reliably.
--
MM
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