What is the minimum number of disk required for RAID-6?

A.
2

B.
3

C.
4

D.
5

Explanation:
RAID-6 is similar to RAID-5. It implements striping with two independent sets of parity across all disks. This allows for the recovery from two simultaneous disk failures and requires an additional disk over RAID-5. RAID-5 requires a minimum of three disks and RAID-6 requires four.
Incorrect
Answers:
A: RAID-0 and RAID-1 require a minimum of two disks. RAID-6 requires a minimum of four disks.
B: A minimum of three disks is required for RAID-5. RAID-6 requires a minimum of four disks.
D: It is possible to use more than four disks for RAID-6, but the minimum is four disks.
References:
Charles J. Brooks, Server+ Certification Exam Cram 2 (Exam SK0-002), QUE Publishing, Indianapolis, 2006, pp. 184-192.
David Groth and Toby Skandier, Network+ Study Guide (4th Edition), Sybex, Alameda CA, 2005, pp. 381-382.