[mythtvnz] Failed recording

[Stephen Worthington]

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
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.

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.

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.