ITPEC FE Morning April 2021 Question 15

RAID 0 — striping spreads data across the disks with no copy and no parity, so the loss of any one disk loses the whole array.

RAID 0 splits data into blocks and writes them to several disks in parallel. Every file is spread over all the disks and nothing redundant is stored, so a single failure leaves every file with holes that cannot be rebuilt. It is less reliable than one disk.

• •RAID 1: mirroring, every write goes to two disks
• •RAID 5: striping with one parity block per stripe, spread over the disks
• •RAID 6: striping with two parity blocks per stripe

Answer (a)

Why not others:

• •(b) RAID 1 — the mirror disk holds a full copy, so the data survives the failure of one disk
• •(c) RAID 5 — the lost disk's blocks are rebuilt from the other disks and the parity, so it survives one failure
• •(d) RAID 6 — two independent parity blocks per stripe let it survive two failures at once

Key rule: RAID 0 adds speed and capacity but no redundancy; every other common level (1, 5, 6) survives at least one disk failure.

System Component · AI-written, may contain errors