[mythtv-users] Commflag-related IOBOUND errors

Yeechang Lee ylee at pobox.com
Wed Jan 18 00:52:02 UTC 2006

Brandon Beattie <brandon+myth at linuxis.us> says:
> Also just so it's known, you can have the best system, raid 10, and
> still get corrupted video.  There are a few things that can cause
> this.  The update scheduled recordings task is nasty in Myth... and
> Mysql can be nasty too.  I see (Weekly) a single recording lose data
> when it spawns this task.

Rescheduling's always seemed pretty lightweight on my setup, but I
*do* see intermittent IOBOUNDs; when they occur, they appear every
five minutes on the dot for 3-8 seconds (:10:02-05, :20:02-08,
:25:02-06, etc.), especially when I'm recording dual HD streams and
especially especially when also watching a third stream, using gigabit
Ethernet and a RAID 1 NAS. I am pretty sure this is related to my
frontend/backend checking for user/commflag jobs every five minutes;
before I changed this from the default setting of every minute, I'd
see the IOBOUNDs pop up in the exact same way (you guessed it) every
minute. (Note, also, that I see the IOBOUNDs even if I'm outside the
2:30-6am time block I've told the backend to run commflag jobs in.)
It's quite possible that this is a swap-related issue and that adding
more RAM to my 512MB system would take care of this, but as a
cheapskate I'm reluctant to do so because I haven't run into any other
memory-related issues I know of.

Yeechang Lee <ylee at pobox.com> | +1 650 776 7763 | San Francisco CA US

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