[mythtv-users] Recordings disappeared

Michael T. Dean mtdean at thirdcontact.com
Tue Jun 29 17:11:26 UTC 2010

On 06/29/2010 10:01 AM, Jason Ward wrote:
> On 29 June 2010 13:26, Brent Bolin wrote:
>> Thanks for both of your replies.
>> I've heard that dirty word "zero-byte on this list but didn't know what it
>> was.
>> Currently only using the option of reserved space that mythtv thinks
>> it needs(off 0).  I can try increasing that.  I have a cron job that
>> reports disk space every hour and right about that time `df -h` was
>> showing about 9GB.  So when this happened it might have been even
>> less.
>> I never saw my freespace fall below 5GB, and thats way enough to take even
> my biggest recording (I have no HD tuners) but my experience/feeling was
> that once free diskspace dipped below 20GB I was only a matter of hours
> before zero byte recording showed up
>> For a couple of hours after this happened I scheduled max recordings
>> to keep all tuners busy.  Didn't see the problem.
>> Yeah, I can't see that for me it was related to the amount of work being
> done by the tuners, I've only got 2, but they can record up to 6 TV channels
> between them (in my current setup) and they've done this several times with
> no problem.

Kevin wasn't talking about a full hard drive (zero available space), he 
was talking about an empty recording file (zero byte size or no file at 

I.e. MythTV writes all the data that your digital capture card gives 
it.  In the case that your capture card is locked up due to system 
hardware or driver issues, MythTV gets exactly zero data--therefore, 
MythTV writes exactly zero data for the recording.

So, fix your hardware or your signal.  Or, since this just started 
happening when you added new capture devices, you may have a broken 
Input Connections configuration (and can clean out the garbage and redo 
it properly with 
http://www.gossamer-threads.com/lists/mythtv/users/264034#264034 ).  A 
broken Input Connections configuration can also put capture card drivers 
into a bad state--or may just be referring to devices improperly meaning 
we don't get any data from them.

Jason's first message referred to the fact that if your system is 
experiencing significant I/O wait--i.e. because you're using the same 
file system (and/or hard drive) for recordings and the MySQL database, 
and the MySQL database is writing a bunch of database data and prevents 
MythTV from writing recording data--you'll get either recording file 
corruption or (if it causes a serious problem at the start of the 
recording) it could even put the capture card into a bad state (as Kevin 
mentioned) and result in the card providing no data to MythTV (after 
buffers fill and aren't properly drained or something).


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