Which of the following provides data the best fault tolerance at the LOWEST cost?

A.
Load balancing

B.
Clustering

C.
Server virtualization

D.
RAID 6

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 thus representing the
lowest cost option.
Incorrect Answers:
A: Load balancing is a way of providing high availability by splitting the workload across multiple computers. This in itself means more costs if you do not already
have the multiple computers.
B: 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).
C: Virtualization is the foundation for cloud computing. You cannot have cloud computing without virtualization. It makes it possible by abstracting the hardware and
making it available to the virtual machines. The abstraction is done through the use of a hypervisor, which can be either Type I (bare metal) or Type II (hosted). It is

not a method used for fault tolerance.

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