RAID 5 Pros: Pros: Pros: Pros: (rotated Balanced Single loss Single loss Only one parity) load. survivable; does not more disk to Potential for prevent power. “in-flight” better read write requests access. response might still become One throughput, corrupted. additional and disk concurrency. required. Three-disk Cons: Cons: Cons: minimum. Cons: Multiple Multiple Up to 4X the Up to 75% losses affect losses power for write entire array. prevent write requests performance a single access to (excluding the reduction loss, array is entire array. idle power). because of vulnerable To until application Decreased access might read be slowed or performance stopped. in failure mode. All sectors must be read for slowdown. Danger of data in invalid state after power loss and recovery.
RAID 5 (rotated parity) One additional disk required. Three-disk minimum. Pros: Balanced load. Potential for better read response throughput, and concurrency. Cons: Up to 75% write performance reduction because of Decreased read performance in failure mode. All sectors must be read for slowdown. Danger of data in invalid state after power loss and recovery. Pros: Single loss survivable; “in-flight” write requests might still become corrupted. Cons: Multiple losses affect entire array. a single loss, array is vulnerable until Pros: Single loss does not prevent access. Cons: Multiple losses prevent access to entire array. To application access might be slowed or stopped. Pros: Only one more disk to power. Cons: Up to 4X the power for write requests (excluding the idle power).
Perf-tun-srv-R2.docx