[mythtv-users] HD recording problem

Chris Bare chris at bareflix.com
Fri Oct 12 14:47:16 UTC 2007

I've just put together a new system for HD mythtv. I am using the HDhomerun
dual tuner, a core2 3Ghz processor and the Seagate 750GB drive.

Last night I had it programmed to record Smallville and My Name Is Earl, both
in HD, both at the same time. While it was recording, I was watching another
show. The playback during recording was fine, but when I watched the recording
of Smallville, it had so many data dropouts (missed frames, broken audio,
scattered macroblocks) that it was unwatchable.
What I find odd is that Earl played back almost perfectly. I've checked CPU
usage, and it is always 10-20% during recording so my best guess is that it's
a disk bandwidth issue. But if that is the case, why wouldn't the dropouts be
scattered between the 2 shows?

Any suggestions on what could be the cause and how to further diagnose it?
are there recommended system performance monitoring tools to run on a myth

In case this is useful, here's the bonnie++ output for my storage partition:
on  1.03       ------Sequential Output------ --Sequential Input- --Random-
                    -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
Machine        Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP  /sec %CP
localhost.locald 4G 66748  88 68523  10 31483   6 73695  87 73377   8 202.2   0
                    ------Sequential Create------ --------Random Create--------
                    -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
              files  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP
                 16   335   1 +++++ +++   264   1   370   1 +++++ +++   250   0

Chris Bare
chris at bareflix.com

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