[mythtv-users] High disk activity

Chris Pinkham cpinkham at bc2va.org
Tue Dec 11 04:00:37 UTC 2007


* On Mon Dec 10, 2007 at 04:44:47PM +0100, Wolfgang Grunewald wrote:
> Chris Pinkham wrote:
> 
> > Besides the fact that LiveTV is reading and writing,
> 
> Sure, the "cat to disk while playing with mplayer" method also
> is reading and writing.

Yes, you are correct, I missed the 'mplayer' part in your post.

The issue is probably the forced sync we do to help promote data
integrity and try to prevent the system from becoming sluggish if
large amounts of data were to have to be flushed to disk.

If you want to play with the sync rate on your system, you can
adjust the numbers upwards in libs/libmythtv/ThreadedFileWriter.cpp
in ThreadedFileWriter::SyncLoop().

> The disadvantages are that a) my box is significantly louder
> (with MythTV I can hear the disk activity e-ve-ry second when
> watching TV, while I usually don't even notice it when using
> the "cat" method) and b) a higher amount of disk drive head
> moves doesn't improve the health of the drive and it maybe
> even leads to higher temperatures.

But higher disk latency due to larger amounts of data being flushed
at the same time can lead to other issues.  We chose to err on the
side of caution and try to prevent recordings from being corrupted.
Touching the source is the only way to modify this behaviour, there
aren't any settings to control this.

--
Chris


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