[mythtvnz] Failed recording

[Worik Stanton]

On 27/09/12 13:43, Stephen Worthington wrote:
> On Thu, 27 Sep 2012 12:44:57 +1200, you wrote:
>
>> On 27/09/12 11:43, Tony Sauri wrote:
>>> On 27/09/12 07:47, Worik Stanton wrote:
>>>>
>>>> The TV3 recording
>>>>
>>>> 2012-09-26 18:00:03.671 Started recording: "News (Manual Record)":"Wed
>>>> Sep 26 18:00:00 2012": channel 1003 on cardid 1, sourceid 1
>>>> 2012-09-26 18:00:03.909 ProgramInfo(1003_20120926180000.mpg), Error:
>>>> GetPlaybackURL: '1003_20120926180000.mpg' should be local, but it can
>> The recording failed.  AT 18:00:03.671 the recording started, at
>> 18:00:03.909 it could not find the file.  But the file does exist.  But
>> it is 4k
>>
>>> And One more question:
>>>
>>> Can you play the file that was created with another tool eg VLC,
>>> mplayer, ffplay etc.?
>>>
>> It is only 4k
> Take a look in /var/log/syslog at the same timestamp - see if there
> was anything there.  That sort of problem can happen when the drive
> was unable to handle all of the reading and writing that is happening
> at the same time.  At the start of a recording, there is heavy
> database and log access as well as the operating system access for
> opening the recording files for writing.  So it is possible that if
> you have too many recordings starting on the same drive as the OS and
> database that the drive may run out of buffering and a write to it

That is a good idea.  But nothing I can notice in syslog...

Sep 26 17:45:04 mythdu CRON[2705]: (CRON) error (grandchild #2706 failed
with e\
xit status 1)
Sep 26 18:00:01 mythdu CRON[2730]: (smmsp) CMD (test -x
/etc/init.d/sendmail &&\
 /usr/share/sendmail/sendmail cron-msp)
Sep 26 18:09:01 mythdu CRON[2776]: (root) CMD (  [ -x
/usr/lib/php5/maxlifetime\
 ] && [ -d /var/lib/php5 ] && find /var/lib/php5/ -depth -mindepth 1
-maxdepth \
1 -type f -cmin +$(/usr/lib/php5/maxlifetime) ! -execdir fuser -s {}
2>/dev/nul\
l \; -delete)




> fails.  What sort of drive is it?  You could try experimenting with
> setting up multiple recordings starting at exactly the same time on
> the same tuner, and then with offsetting the starting times by say one
> minute, and see if having them start at the same time overstresses
> things.  Modern hard drives are easily capable of writing three
> recording files at once, after the recordings have started, but all
> the extra head movement for accessing database and log files at the
> start can possibly be too much.

Ok.  I'll do that.  I'll start one of the 18:00 recordings early


>
> Also, do you have mythcommflag set up to start processing the
> recordings as soon as they start?  Unless your processor is fast
> enough, mythcommflag will be getting the data back out of the
> recording files on disk and adding to the load.  My new motherboard
> seems to be fast enough for mythcommflag to keep up in real time and
> hence be able to use the data in the write buffers before it gets to
> disk, but with my old motherboard mythcommflag lagged behind and
> needed disk access.

I have not noticed that setting.  Frankly I find the commercial
detection too unreliable to use.  That is one of my jobs - to see if I
can make that work.  In the mean time I might just turn it off.

>
> There is also a deadlock bug in 0.24+fixes, which I have run into a
> number of times, that causes your exact error message.  That bug
> normally causes there to be no recording file though, rather than a
> tiny one, and I have only had it when recording three or more things
> on multiple tuners.  And you know it has happened as there are
> messages in the MythTV log that are very characteristic and
> mythfrontend stops responding correctly (some things still work, but
> many do not), until you restart mythbackend.

Hmmm...

Have you a reference for that bug?  Since I am running 0.24 I should
investigate that.

thanks
Worik


-- 
it does not matter                      I think that I shall never see
how much I dig and dig                    A billboard lovely as a tree
this hole just                      Indeed, unless the billboards fall
keeps getting deeper                      I'll never see a tree at all