IPA IP 2023 Question 63
A question IPA Japan published in 令和5年度 ITパスポート試験 公開問題 問63, translated into English. ITPEC is based on the same exams.
When RAID0 and RAID1 are configured by using two (2) HDDs with a capacity of 500 GB, which of the following is the appropriate combination of the storage capacities that can actually be used?
Explanation
RAID0: 1 TB, RAID1: 500 GB — striping adds the disks' capacities together; mirroring stores everything twice, so only one disk's worth is usable.
- •RAID0 (striping): data is split across both disks with no redundant copy, so all of their capacity holds data: 500 + 500 = 1000 GB = 1 TB. It is fast, but if either disk fails the data is lost.
- •RAID1 (mirroring): the same data is written to both disks, so the second disk holds only a copy: usable capacity is 500 GB. If one disk fails, the other still has all the data.
Answer (b)
Why not others:
- •(a) — gives RAID1 the full 1 TB, forgetting that each mirrored disk holds the same data
- •(c) — swaps the two: it is RAID1, not RAID0, that halves the capacity
- •(d) — halves RAID0 too, but striping keeps no copy and uses every disk in full
Key rule: With n equal disks, RAID0 gives n disks of capacity and no redundancy; RAID1 gives one disk of capacity and survives a disk failure.
System Component · AI-written, may contain errors
This question comes from the past questions IPA Japan publishes, translated into English by ITPEC Practice. ITPEC Practice is an independent study tool and is not affiliated with IPA or ITPEC. See the original paper (PDF) or Report an issue.