Which RAID level provides double parity and can tolerate up to two simultaneous disk failures?

Which RAID level provides double parity and can tolerate up to two simultaneous disk failures?

• A. RAID 6
• B. RAID 5
• C. RAID 1
• D. RAID 10

Answer: (A)

Double parity means two separate parity calculations are stored across the disks, so you can recover the entire array even if two drives fail at the same time. RAID 6 uses this approach, allowing up to two simultaneous disk failures without data loss because the two parity blocks provide enough information to reconstruct the missing data from the remaining disks. This contrasts with RAID levels that rely on a single parity block, which can only tolerate one failure. Mirroring stores exact copies on separate disks, offering protection against a single drive failure, but it isn’t designed around the same two-failure parity fallback. RAID 10 mixes striping and mirroring for redundancy, but its fault tolerance isn’t based on double parity, so the two-disk failure protection you get with double parity is unique to RAID 6.

Double parity means two separate parity calculations are stored across the disks, so you can recover the entire array even if two drives fail at the same time. RAID 6 uses this approach, allowing up to two simultaneous disk failures without data loss because the two parity blocks provide enough information to reconstruct the missing data from the remaining disks.

This contrasts with RAID levels that rely on a single parity block, which can only tolerate one failure. Mirroring stores exact copies on separate disks, offering protection against a single drive failure, but it isn’t designed around the same two-failure parity fallback. RAID 10 mixes striping and mirroring for redundancy, but its fault tolerance isn’t based on double parity, so the two-disk failure protection you get with double parity is unique to RAID 6.