An administrator must create a single array on a new database server. The workload requires that the array stay online if one physical disk fails, provide better write performance than a dual-parity solution, and maximize the usable capacity of eight identical 1.8 TB 12 Gb/s SAS drives connected to a hardware controller that supports RAID 0, 1, 5, and 10. Which RAID level best meets these requirements, and approximately how much usable space will the array provide?
RAID 5 distributes single-parity blocks across all eight disks, allowing the array to tolerate one drive failure while keeping read performance high and write overhead lower than a dual-parity RAID 6. Because only the equivalent capacity of one disk is reserved for parity, usable capacity is (8 − 1) × 1.8 TB ≈ 12.6 TB. RAID 6 would protect against two failures but would consume two disks of capacity (≈ 10.8 TB) and add extra write overhead; RAID 10 would mirror half the disks, leaving about 7.2 TB; RAID 0 would supply the full 14.4 TB but no redundancy, so it does not satisfy the fault-tolerance requirement.