CompTIA A+ Core 1 (220-1201)HardwareMedium
A technician is configuring a RAID 5 array using four 2TB hard drives. Approximately how much usable storage capacity will the array provide?
- A4TB
- B8TB
- C6TB
- D2TB
Show answer & explanationAnswer & explanation
Correct answer: C. 6TB
RAID 5 uses distributed parity equal to one drive's capacity, so usable space equals (n-1) × drive size. With 4 drives of 2TB: (4-1) × 2TB = 6TB usable.
Why the other options are wrong
- A. 4TB underestimates capacity; that would only account for two drives worth of data.
- B. 8TB would be the raw total capacity without accounting for parity overhead.
- D. 2TB would only be usable capacity for a mirrored two-drive RAID 1 setup.
RAID 5 Capacity
RAID 5 stripes data with distributed parity across all disks, sacrificing one disk's worth of capacity for fault tolerance.
- Formula: usable = (n-1) × drive size
- Requires minimum 3 drives
- Can survive failure of exactly one drive
Memory trick: RAID 5 = lose one drive's worth to parity, keep the rest