ITPEC FE Morning October 2023 Question 16
Topic: System Component
Which of the following is an RAID configuration that deploys two parity records to different disk drives enabling two simultaneous disk drive failures in the same RAID group to be recovered?
Explanation
RAID6 — it writes two independent parity blocks per stripe to different drives, so any two failed drives in the group can be rebuilt.
- •RAID0: striping only, no redundancy; one failure loses data
- •RAID1: mirroring, a full copy on a second drive; no parity
- •RAID5: striping with one distributed parity block; survives one failure
- •RAID6: striping with two distributed parity blocks; survives two simultaneous failures
Answer (d)
Why not others:
- •(a) RAID0 — has no parity or copy at all, so it cannot recover even one failed drive
- •(b) RAID1 — protects by duplication, not by parity records
- •(c) RAID5 — has a single parity block per stripe, so a second failure during rebuild loses data
Key rule: Each parity block per stripe allows one drive failure to be recovered: RAID5 has one, RAID6 has two.
System Component · AI-written, may contain errors
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