[ale] Tweaking raid rebuild time

[Christopher Fowler]

I've got a dual-core system that I'm testing mdtools raid rebuild time.
Right now it is averaging below 2 hours.  I would like to cut the time
in half.

1: 99%   Rebuild complete in 4086(s)
2: 99%   Rebuild complete in 6549(s)
3: 99%   Rebuild complete in 6309(s)
4: 99%   Rebuild complete in 6489(s)
5: 99%   Rebuild complete in 6550(s)
6: 99%   Rebuild complete in 6309(s)

I do not care if my load jumps to 1+ during the rebuild.  I just want it
to happen quickly.  Can someone tell me the proper tuning for the raid
files in /proc that can assist me?

Chris