[sclug] RAID stuff again

[James Fidell]

Quoting Matt (matt at bodgit-n-scarper.com):

> No, I think I've got this wrong.
> 
> I think there is a guaranteed *minimum* rebuild rate. Therefore fairly
> sure it should go as fast as it can.

No, you were right the first time.  The logs should contain something
like this:

md: minimum _guaranteed_ reconstruction speed: 100 KB/sec/disc.
md: using maximum available idle IO bandwith (but not more than 100000 KB/sec) for reconstruction.

James