SoulBlazer wrote:

Can you share 2 or 3 'spare-disks' between multiple raid sets?

Eg. I have a 22 disk array chopped into multiple 4 disk raid-5 volumes, this 
leaves me with 2 disks left over..  Can I assign these two drives as floating 
spares incase of failure.. this will obviously be a 'first come first serve' 
scenario for raid failure.. but its better then not using them.

I'm sure you could script something to that effect based on the current 
RAID tools and their options/output...

If there's nothing like it already included (I haven't checked - and no 
in-depth knowledge of raid tools either, so forgive any stupid remarks) 
I could imagine a cron job checking the logs for disk failures and 
hot-adding the "new" disk (one of the spares, if available).

Interesting idea!

Marcel