[mythtv-users] High disk activity

Wolfgang Grunewald wmgrunewald at web.de
Mon Dec 10 15:44:47 UTC 2007


Chris Pinkham wrote:

> * On Sun Dec 09, 2007 at 11:34:02PM +0100, Wolfgang Grunewald wrote:
> >   http://tinyurl.com/22xppv
>
> There's some woman blocking the view in this graph.

Sorry for that! The MythTV graph shows constant disk activity
while the "cat while playing with mplayer" graph just shows
some high writing peaks every few seconds (besides that
there's no activity at all).

> > When I record the stream "manually" using
>
> >   http://tinyurl.com/26x2oj
>
> Besides the fact that LiveTV is reading and writing,

Sure, the "cat to disk while playing with mplayer" method also
is reading and writing.

> it could also be attributed to the fact that Myth calls sync() to
> force flushing to disk while your manual 'cat' just lets the OS
> decide when to flush to disk.

Is it possible to change / configure that? If yes, how?

> > (Looks like the HD cache is not being used at all.)
>
> Sounds like this may be what you're seeing them.
>
> > What can I do to reduce the high disk activity?
>
> It's not really high, just more visible on the graphs.  It's
> writing the same amount of data out to disk, Myth just spreads it out
> more while your 'cat' is being dumped to disk in larger chunks by the
> OS.

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.

Wolfgang
@Brian: RAM is not a problem. I still have 500 MB free while
running MythTV.
_______________________________________________________________________
Jetzt neu! Schützen Sie Ihren PC mit McAfee und WEB.DE. 3 Monate
kostenlos testen. http://www.pc-sicherheit.web.de/startseite/?mc=022220



More information about the mythtv-users mailing list