[mythtv-users] "TFW, Error: Write() -- IOBOUND" 8 minutes long!

[Douglas Peale]

I have been having picture breakups in my recordings lately. Looking in my backend logs I noticed that they seemed to correlate
to "TFW, Error:Write() -- IOBOUND" errors. Most of them are short, on the order of seconds, but this one:

2011-02-21 22:56:51.280 TFW, Error: Write() -- IOBOUND begin remaining(4865) free(0) size(4194304) cnt(1)
2011-02-21 22:57:00.738 Player(0): Timed out waiting for free video buffers.
2011-02-21 23:05:02.603 TFW, Error: Write() -- IOBOUND end

is over 8 minutes long, and corresponded with the missing ending of a recording.

The system is an i7 processor with 6 GB of ram and a 1.5 TB SATA drive. The only slightly unusual thing I am doing on my system
is starting the commercial flagging as soon as the recording starts. The assumption being this should reduce disk accesses since
the data should still be in the disk cache when the commercial flagger tries to read it.

I assume the normal behavior would be worse since it would start commercial flagging the moment the recording ended, the
recording would be bigger than the disk cache, so the beginning of the file would already have been dumped from the cache, and
if a second recording had started, the second recording would be fighting with the commercial flagger for disk bandwidth.

Am I making a bad assumption here? Should I just go out and get a SSD for the system, and use the existing drive only for
recordings?

Is there any way to get MythTV to buffer to RAM when the disk drive gets bottlenecked? 6GB of ram should be good enough for a 30
minute ring buffer.

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