[mythtv-users] Tracking down backend issues

Bill Omer bill.omer at gmail.com
Wed Nov 14 02:30:08 UTC 2007

I'm having some issues with my backend and I'm looking for some
guidance.  I've replaced my motherboard, cpu and memory, upgrading
from a 1.2GHz Athlon to a 2.7GHz P4 Celeron.  I'm currently only using
512 megs of ram, but I've only used 33 megs of swap.  I had these
exact same problems using my previous backend with 768MB of ram.  The
hard drives are the same (ata), there's an average of about 18% iowait
according to iostat when recording three shows, watching a show and
commflagging two shows.

The first, and most annoying problem, is when I try to go to Watch
Recordings, it sometimes will not show the group summery at all.  I
have to restart the frontend, sometimes several times, before the
group summery will appear.  I've watched top while this happens, and
mythbackend starts to use 99% of the available cpu.  I've also noticed
the following in my mythbackend.log:

2007-11-13 21:03:10.036 MythSocket(ab064198:-1): writeStringList:
Error, socket went unconnected.
2007-11-13 21:03:10.493 MythSocket(aa43a3f0:-1): writeStringList:
Error, socket went unconnected.
2007-11-13 21:03:10.933 MythSocket(ab47e4b8:-1): writeStringList:
Error, socket went unconnected.

My next problem is with watching an HD program while it's being
recorded.  I am able to watch live tv with my hd tuner, but when I
watch an hd program while its being recorded, the playback is very
choppy and unwatchable.  Here's a snippet from my mythbackend.log:

2007-11-13 21:04:06.731 DevRdB(0) Error: Driver buffers overflowed
2007-11-13 21:04:06.792 TFW, Error: Write() -- IOBOUND begin cnt(9588)
2007-11-13 21:04:06.946 TFW, Error: Write() -- IOBOUND end

And my last problem is when I try to open the program guide while
watching live tv, it takes a *very* long time before it shows up.
I've seen the same "socket went unconnected" message in my backend

Any advice on how to trouble shoot this further would be greatly appreciated.

Bill Omer

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