ITPEC IP April 2022 Question 16
Among the methods I through III for handling multiple hard disks as one (1) logical disk, which of the following lists all and only the methods that can recover data even if one of the constituent hard disks fails?
Explanation
I and III — RAID5 and mirroring keep redundant data, so the contents of one failed disk can be recovered; striping keeps none.
- •I RAID5 spreads data and parity blocks across the disks; a failed disk's contents are rebuilt from the data and parity on the others
- •II Striping (RAID0) splits data across the disks for speed only; with no copy or parity, one failed disk loses data
- •III Mirroring (RAID1) writes the same data to two disks, so the surviving disk still holds everything
Answer (c)
Why not others:
- •(a) — includes striping, which has no redundancy, and leaves out mirroring
- •(b) — includes striping
- •(d) — includes striping and leaves out RAID5, whose parity allows recovery
Key rule: Recovery after a disk failure needs redundancy: mirroring keeps a copy, RAID5 keeps parity, and striping alone (RAID0) only adds speed.
System Component · AI-written, may contain errors
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