CISA Practice Question: Information Systems Operations and Business Resilience

An organization uses RAID 5 for its database server. Which of the following is the PRIMARY advantage of RAID 5?

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

✓

Fault tolerance with one disk failure

RAID 5 provides fault tolerance with parity, allowing recovery from a single disk failure.

Answer analysis

For each option: why learners choose it and why it is or isn't the right answer here.

✗
Simplified backup process
Why it's wrong here
RAID does not replace backups.
✗
Increased storage capacity without parity overhead
Why it's wrong here
RAID 5 uses parity, so overhead exists.
✓
Fault tolerance with one disk failure
Why this is correct
This is the primary advantage.
✗
Improved read performance
Why it's wrong here
RAID 5 does improve read performance, but fault tolerance is primary.

Quick reference

RAID Level	Min Disks	Fault Tolerance	Read	Write	Usable Capacity
RAID 0	2	None	Excellent	Excellent	100%
RAID 1	2	1 disk	Good	Moderate	50%
RAID 5	3	1 disk	Good	Moderate	67–94%
RAID 6	4	2 disks	Good	Lower	50–88%
RAID 10	4	1 disk per mirror	Excellent	Good	50%

RAID is not a backup strategy — it protects against disk failure but not against accidental deletion, ransomware, or site-level events.

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