Which of the following statements BEST describes clustering?

A.
Upgrading server performance by adding components to the server.

B.
Adding additional servers and implementing load balancing.

C.
Configuring multiple servers that act as a single unit.

D.
The ability of server system’s software, hardware, and components to adapt to increasing demand as a result of network growth.

Explanation:
Configuring two or more servers to act as one is referred to as clustering.
Incorrect
Answers:
A: The process of adding components or upgrading existing components in a server is referred to as scaling up.
B: The process of adding additional servers and implementing load balancing between the servers is referred to as scaling out.
D: A server system’s ability to handle increased demand which may result from future network growth, is referred to as scalability.
References:
Charles J. Brooks, Server+ Certification Exam Cram 2 (Exam SK0-002), QUE Publishing, Indianapolis, 2006, pp. 39-45.