[mythtv-users] IOBOUND during mythfilldatabase

Glenn glenn at saskatoon.com
Fri Feb 23 19:41:35 UTC 2007


I've searched through the mailing list without finding any good resolution to 
my problem.  This sounds similar but the ticket was closed as invalid:

http://www.mythtv.org/pipermail/mythtv-commits/2005-September/007946.html

This is what is happening.  When mythfilldatabase runs the backend logs these 
types of errors:
2007-02-23 13:14:33.947 TFW, Error: Write() -- IOBOUND begin cnt(2048) 
free(2047)
2007-02-23 13:14:37.074 TFW, Error: Write() -- IOBOUND end

Sometimes it just becomes unresponsive while at other times it actually 
crashes and I have to restart it.

I don't believe that it is just a system performance issue but could certainly 
be related to some settings or configuration.  My original backend server was 
a dual PII - 333MHz with 192MB ram.  It worked perfectly though a little slow 
for commercial flagging, etc.  

I recently upgraded to a Athlon 64 - 3200 with 1GB of ram. I kept the same 
drives (Seagate 160GB in Raid 1).  I am using ext3 and dma seems to be turned 
on.  I installed fedora core 6 at the same time as the hardware change and 
moved to myth 0.20.  I should point out the I am recording 1 stream on a 
PVR500 and that this is a BE only.  During normal recording I see mythbackend 
only uses 1-2% cpu.

If I look in top during mythfilldatabase I can see as much as 95% wa.  

What direction should I look in?  Is this a disk bandwidth problem?  A mysql 
problem?





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