Chapter 9: Fault Tolerance and Disaster Recovery

Overview

NETWORK+ EXAM OBJECTIVES COVERED IN THIS CHAPTER:

• 3.5 Identify the purpose and characteristics of fault tolerance.

• 3.6 Identify the purpose and characteristics of disaster recovery.

Computers are not perfect. They can (and do) have problems that affect their users’ productivity. These problems range from small errors to total system failure. Errors and failures can be the result of environmental problems, hardware and software failure, hacking (malicious, unauthorized use of a computer or a network), as well as natural disasters.

In all cases, you can take measures to minimize the impact of computer and network problems. These measures fall into two major categories: fault tolerance and disaster recovery. Fault tolerance is the capability of a computer or a network system to respond to a condition automatically, usually resolving it, and thus reducing the impact on the system. If fault-tolerant measures have been implemented, it is unlikely that a user would know that a problem existed. Disaster recovery , as its name suggests, is the ability to get a system functional after a total system failure (a disaster for a company and the network administrator) in the least amount of time. Strictly speaking, if enough fault tolerance methods are in place, you shouldn’t need disaster recovery.

Both methods are important and are implemented on most, if not all, networks. Because of this, the Network+ exam will test you on your knowledge of the most popular implementations of fault tolerance and disaster recovery. In this chapter, we will look at the following:

• How to assess fault tolerance and disaster recovery needs

• Power management

• Disk system fault tolerance methods

• Backup considerations

• Virus protection