and even then, IMO, you'd be better off using, say, 240GB SSDs rather than 300GB SAS drives - 20% less storage but many times the IOPS, for roughly the same price. even 500-ish GB SSDs aren't that much more than 600GB 15k SAS disks, about $860 for a 480GB Intel 520 vs about $575 for an IBM 15k 600GB SAS....80,000 IOPS vs what, maybe 1000?
According to the HP Configureaider: 300GB 2.5" 10KRPM SAS - $422 300GB 2.5" 15KRPM SAS - $772 200GB 2.5" MLC SSD SAS - $4696 I'd be careful about sticking your $860 SSD into a server if you require any sort of write performance or durability, you might find you get just what you paid for. OTOH, if your workload is read-only (or read-mostly), a cheap(er) SSD may be well worth the investment vs 15KRPM disks.
(*) a large part of the point of RAID is that it is a Redundant Array of *Inexpensive* Disks. enterprise drives fail on that particular point. the disks are meant to be cheap and replacable commodity parts.
... or Redundant Array of *Independent* Disks, as if the name tells you what sort of disks you should be using anyway. At 15KRPM you can read a single track in half the time, and therefore twice the speed. You would also get additional gyroscopic stability although I don't know if that makes a difference in reality... someone (on LUV I think) mentioned that consumer grade disks performance suffered much more when placed in an environment with vibration (eg adjacent to other seeking disks in a server). James