[mythtv] Ticket #2335: LiveTV hangs when a recording is finished and a new on starts (no channel change)

mythtv at miwers.dk mythtv at miwers.dk
Wed Jul 25 22:03:34 UTC 2007

eric.bosch at comcast.net wrote:
> I don't believe it is an ivtv issue, as I can have the live-tv hang on 
> show transition, even though the program is scheduled to record, and 
> once I can get back to the menu, and then play it back from recordings, 
> it plays fine.  My suspicion is that there is some sort of race 
> condition or timing issue in that perhaps there is a short delay where 
> the new file is opened, and actually catalogged.   What kind of 
> filesystem implementations are you running?  I have an LVM managed set 
> of virtual drives, one of which being a 500GB filesystem for the 
> recordings.  My backend uses NFS filesystem for the recordings, and both 
> frontends are configured to stream from remote server.  If I don't do 
> this, then I have severe stuttering and eventual stall on livetv from 
> remote tuners.

Yeah, you're right...

My setup consists of one backend server also acting as a frontend, and a 
second frontend machine streaming from the backend server. All testing 
is done on the locally on the backend.

All recording happens to a separate 250GB physical SATA disk on the 
backend with a reiserfs partition. Here are some hdparm timing tests, 
for what it's worth:

server ~ # hdparm -Tt /dev/sda1

  Timing cached reads:   898 MB in  2.00 seconds = 449.10 MB/sec
  Timing buffered disk reads:  148 MB in  3.01 seconds =  49.23 MB/sec

  Timing cached reads:   962 MB in  2.00 seconds = 480.36 MB/sec
  Timing buffered disk reads:  160 MB in  3.02 seconds =  53.04 MB/sec

  Timing cached reads:   1014 MB in  2.00 seconds = 506.58 MB/sec
  Timing buffered disk reads:  156 MB in  3.02 seconds =  51.59 MB/sec


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