Compaq 3200 manual Understanding Drive Arrays, What is a Drive Array?

E-1

Appendix E

Understanding Drive Arrays

This chapter explains drive array concepts, data protection methods (including fault-tolerance options), and data reliability features of the Smart Array 3200 Controller. The following general information will help you understand terms and concepts required for configuration.

What is a Drive Array?

A drive array is a collection of hard disk drives or physical drives that are grouped together to create an array of physical drives. An array is made up of one or more subsets called logical drives (sometimes called logical volumes), that are spread across all physical drives in the array. Operating systems view logical drives as a single, contiguous storage space, although it is made up of parts of several physical drives.

The generic drive array illustrated in Figure E-1 consists of two logical drives spread across three physical drives. Figures E-2 through E-4 illustrate other drive array configurations.

Physical	Physical	Physical
Drive 1	Drive 2	Drive 3

Logical

Drive 1

Logical

Drive 2

Drive Array

Figure E-1. Drive array with two logical drives

Compaq Smart Array 3200 Controller Reference Guide