Problem with RAID is not just drives failing, but also the UBE (Unrecoverable Bit Error). Lets say you have a RAID5 configuration. In addition to the probability of disk failure, you need to account for the probability of some failure plus the controller's inability to repair the problem because a sector on the good disks experienced an UBE. The probability of UBE on enterprise level disks is rather low (10^-16 I think) but that quickly shoots up if you start considering 1TB and 2TB drives.
Problem with EBS benchmarks is that they largely depend on who else is sharing the spindles with you at the time the benchmark was run. Given the large variance in performance that is being reported, the sample size for some reliable statistics would need to be quite large
Problem with EBS benchmarks is that they largely depend on who else is sharing the spindles with you at the time the benchmark was run. Given the large variance in performance that is being reported, the sample size for some reliable statistics would need to be quite large