Which statement about RAID 5 parity is correct?

• A. RAID 5 parity is stored on a single dedicated disk.
• B. RAID 5 parity is not used in data protection.
• C. RAID 5 uses fixed parity disks.
• D. RAID 5 uses parity computed by XOR across disks.

Answer: (D)

Parity in RAID 5 is computed by XOR across disks and is distributed across the array rather than housed on a single drive. This means for each stripe, data blocks are stored on multiple disks and a parity block is created as the XOR of those data blocks. Across stripes, the location of that parity rotates so no single disk always holds parity. If one disk fails, you can reconstruct its missing data by XORing the remaining data blocks with the parity block. This protection method relies on the reversible properties of XOR to recover lost information. The other statements don’t fit because parity isn’t fixed on one disk (that would be RAID 4), parity is indeed used for protection, and parity is not stored on fixed disks but distributed.