Visiting philip.greenspun.com and entering "RAID" into the search engine brought me to http://philip.greenspun.com/wtr/dead-trees/db-choosing.html which specifically states:
"The first thing you do is mirror all of your disks. If you don't have the entire database in RAM, this speeds up
SELECTs because the disk controller can read from whichever disk is closer to the desired track. The opposite effect
can be achieved if you use "RAID level 5" where data is striped across multiple disks. Then the RDBMS has to wait
for four disks to seek before it can cough up a single row. So mirroring, or "RAID level 0", is what you want."
That's all I know, so if someone proves me wrong, that's not a big deal since I don't do this stuff for a living.
I admit that it's been a long time since I've personally handled Oracle running on a large site. I'm rather surprised to hear that your box is maxed out on its CPUs, though. What's eating up the CPU cycles?
