But what about RAID?
Wednesday, March 17, 2010
5:01 PM
But what about RAID? 
Point of RAID: one failure in 5 doesn't cause data loss/downtime
So, we're more concerned with whether 2 fail at the same time (independent events) than whether one fails. 
Downtime for 1 failure=0 (response time changes)
Downtime for 2 failures= substantive (recover from backup or image). 