[ILUG] Ram disking part of a file-sysem

[Greg Farrell]

Heya,

   I'm using mythtv as a pvr right now, and love it. The version I use
- .18 uses a seperate mount point for live tv data as opposed to for
recording programs.

   So I was planning on making this live tv ring-buffer a 512mb ram disk
which should allow me to spin the hard-drive down while watching tv.
Only using the hard-drive when I'm recording a show. This is because
it's a mini-itx system in a very small case and since I got some 14db
fans the hard-drive is the loudest and probably hottest component (3 1/2
inch drive).

   However in an evil conspiracy they went and released .19 last week
which merges the ringbuffer and the normal recording directory. This has
some nice benefits such as you can press record while watching live tv
and it'll save the parts of the program you've already watched as well.
However it means I can't have a seperate ram disk partition for live tv.

   Any ideas on how I can spin down the hard drive and yet still be
recording data destined for it? I was thinking that perhaps I could up
the commit interval to something ridiculous like 500mb so it would only
spin up rarely. However I can find no documentation on that for jfs the
file-system I use (as recommended by mythtv). If it's possible on
another such as xfs or what-not I'd be willing to give them a go.

  A gig of ram is the max my machine will take and it's over 2 gigs of
data an hour, so writing to a ram disk and then copying the end data
elsewhere afterwards won't work I think.

  Neither would an external compact flash key with jffs, unless it was
huge, and hence very expensive.

  I see this as more of a Linux fs/caching question than mythtv specific
hence asking here.

   thanks,
      Greg