For 3 years we had an LSI SAN with 48, 300GB Segate Cheetah 15K.5 (Model ST3300655FC) 3.5-inch drives. There are about 7 drives failed total. There bulk failed recently. Six drives since May 2010.
That's at a rate of 0.02 (drives failed)/(month)/(drives in array) for the last 6 month period.
There is an older SAN from HP running in the same room, I the drives are probably 15K 36 GB. Those never failed.
Is it common that 300GB 15K RPM drives start failing at this rate after 3 years?