A small business needs to incorporate fault tolerance into their infrastructure to increase data availability. Which of the following options would be the BEST solution
at a minimal cost?

A.
Clustering

B.
Mirrored server

C.
RAID

D.
Tape backup

Explanation:
RAID, or redundant array of independent disks (RAID). RAID allows your existing servers to have more than one hard drive so that if the main hard drive fails, the
system keeps functioning. RAID can achieve fault tolerance using software which can be done using the existing hardware and software.
Incorrect Answers:
A: Anytime you connect multiple computers to work/act together as a single server, it is known as clustering. Clustered systems utilize parallel processing
(improving performance and availability) and add redundancy (but also add costs).
B: Mirrored server implies that you have a mirror / duplicate of the server which will provide you with 100 % redundancy, but it does not represent the least cost
option.
D: Tape Backup will also incur costs and is means for backing up data to mitigate a loss.

Dulaney, Emmett and Chuck Eastton, CompTIA Security+ Study Guide, Sixth Edition, Sybex, Indianapolis, 2014, pp 34, 234, 235