Data Availability

For many companies, computing systems have become such an integral part of their business that severe consequences can occur when they are unavailable. These systems are used for critical business functions such as order processing and tracking, inventory control, transaction processing, customer support, and electronic commerce. When these critical functions are not accessible, it can result in lost revenue, lost productivity, reduced customer satisfaction, possible data loss or reduced decision making capabilities. As a result, in today's global environment, these computing systems must be available 24 hours per day, 365 days per year.

Improved availability must balance the cost of downtime against the cost of any proposed solution in order to find the most cost-effective method of availability. The first consideration should be the basic quality and reliability of the server (to minimize failures). Dell servers, from the dual-processor to high-end eight-processor servers, have been designed with a broad array of redundant features to maximize a server's availability. The first step to a higher availability is the implementation of RAID.

Section Objectives

After completing this module, you will be able to:

Describe the purpose of RAID, and the most popular RAID levels.
Describe a PERC, its features, and benefits.
Describe high availability clustering.