Which statement summarizes the redundancy and performance characteristics of RAID 1, RAID 5, RAID 6, and RAID 10?

Which statement summarizes the redundancy and performance characteristics of RAID 1, RAID 5, RAID 6, and RAID 10?

• A. RAID 1 mirrors; RAID 5/6 use parity with distributed checksums; RAID 10 combines mirroring and striping for good redundancy and performance.
• B. RAID 5 parity with distributed checksums; RAID 1 mirrors; RAID 10 relies on mirroring and striping for performance.
• C. RAID 6 uses double parity with striped data; RAID 5 uses single parity; RAID 1 mirrors; RAID 10 is striped only.
• D. RAID 10 combines mirroring and striping; RAID 5/6 provide no redundancy; RAID 1 uses parity.

Answer: (A)

Redundancy and performance in RAID levels come from how data is stored across disks. RAID 1 uses mirroring, so each piece of data is kept as an exact copy on another disk, giving strong fault tolerance and typically good read performance because reads can be served from multiple disks, though writes must be duplicated. RAID 5 and RAID 6 both use parity to recover data if a disk fails; parity bits are distributed across the drives. RAID 5 uses a single parity block, while RAID 6 adds a second parity block, allowing it to survive two simultaneous disk failures. This parity-based approach protects data but introduces a write penalty because parity must be updated with every write. RAID 10 combines mirroring and striping, offering high redundancy and strong performance by maintaining mirrored pairs and striping data across those pairs. The statement that best captures these ideas is that RAID 1 is mirroring; RAID 5 and RAID 6 rely on parity with distributed checksums; and RAID 10 combines mirroring and striping for good redundancy and performance. The other descriptions either omit key details (like double parity for RAID 6) or misstate how certain levels provide redundancy or performance.

Redundancy and performance in RAID levels come from how data is stored across disks. RAID 1 uses mirroring, so each piece of data is kept as an exact copy on another disk, giving strong fault tolerance and typically good read performance because reads can be served from multiple disks, though writes must be duplicated. RAID 5 and RAID 6 both use parity to recover data if a disk fails; parity bits are distributed across the drives. RAID 5 uses a single parity block, while RAID 6 adds a second parity block, allowing it to survive two simultaneous disk failures. This parity-based approach protects data but introduces a write penalty because parity must be updated with every write. RAID 10 combines mirroring and striping, offering high redundancy and strong performance by maintaining mirrored pairs and striping data across those pairs.

The statement that best captures these ideas is that RAID 1 is mirroring; RAID 5 and RAID 6 rely on parity with distributed checksums; and RAID 10 combines mirroring and striping for good redundancy and performance. The other descriptions either omit key details (like double parity for RAID 6) or misstate how certain levels provide redundancy or performance.