CompTIA A+ Core 1 (220-1201)Hardware and Network TroubleshootingHard
A small business wants to configure a RAID 10 array using four 2TB drives to maximize both redundancy and performance. How much usable storage capacity will the array provide?
- A8TB
- B4TB
- C2TB
- D6TB
Show answer & explanationAnswer & explanation
Correct answer: B. 4TB
RAID 10 mirrors pairs of drives and then stripes across the mirrored sets. With four 2TB drives, capacity is: total raw = 4 x 2TB = 8TB, then divided by 2 for mirroring = 8TB / 2 = 4TB usable capacity.
Why the other options are wrong
- A. 8TB is the raw total capacity, not the usable capacity after mirroring overhead.
- C. 2TB would only be correct for a single mirrored pair, not the full four-drive array.
- D. 6TB would apply to a RAID 5 configuration with four drives, not RAID 10.
RAID 10 Capacity Calculation
RAID 10 (1+0) combines mirroring and striping; usable capacity always equals half of the total raw capacity of all drives combined.
- Requires a minimum of 4 drives
- Usable capacity = (number of drives x drive size) / 2
- Offers both fault tolerance and improved read/write performance
Memory trick: 'Ten Takes Half' — RAID 10 always halves your raw total.