[mythtv-users] Running mythfilldatabase while recording

Bruce Markey bjm at lvcm.com
Sun Apr 8 05:45:04 UTC 2007

Yeechang Lee wrote:
> Bruce Markey <bjm at lvcm.com> says:
>> Also, don't run mfdb while something is recording if you can help
>> it. More joy.
> I didn't realize this was a potential problem. Is it that the database
> can get damaged somehow?

No but there is the potential that frames could be dropped
in a recording if there is latency due to resource contention.

> Or that on less-robust systems
> mythfilldatabase puts enough of a stress on the filesystems,
> scheduler, memory, etc. so as to cause skips in the recording?

It will max out any resource it needs whether it is a 286 or
a really expensive machine with lots of blinking lights. Mfdb
is CPU intensive and mysqld is constantly being hammered and
constantly hammering I/O in turn reading and writing changes.

Given the choice of running while recording and while not
recording, I choose not recording.

I nice down mysqld a little and mfdb a lot. There's no rush
and these should yield to anything that wants a resource. It
can wait, it'll finish.

Writing recordings should only take a small fraction of the
I/O throughput. However, data is arriving at a steady pace
and it can not afford to fall too far behind due to latency.

--  bjm

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