Chapter SEVEN. Disk Array Technologies

Chapter Syllabus

7.1 Drive Array Technologies

7.2 RAID Technology Overview

7.3 RAID Implementation

7.4 RAID 0 Disk Striping

7.5 RAID 1 Disk Mirroring

7.6 RAID 1+0 Striped Mirror Sets

7.7 RAID 2 Data Sector Striping with ECC

7.8 RAID 3 Parity Check

7.9 RAID 4 Data Guarding

7.10 RAID 5 Distributed Data Guarding

7.11 RAID AD Advanced Data Guarding

7.12 RAID Level Performance Comparison

After studying this chapter, you should be able to:

• Define drive array and explain the concept of logical drives.

• Define RAID, list RAID benefits, and describe the key features and capabilities of RAID.

• Explain the differences between software- and hardware-based RAID.

• Explain the advantages that hardware-based RAID has over software-based RAID.

• Explain how RAID 0 works and list its advantages and disadvantages.

• Explain how RAID 1 works and list its advantages and disadvantages.

• Explain how RAID 1+0 works and list its advantages and disadvantages.

• Explain how RAID 3 works and list its advantages and disadvantages.

• Explain how RAID 5 works and list its advantages and disadvantages.

• Explain how RAID ADG works and list its advantages and disadvantages.

• Compare and contrast the current-industry RAID levels.

A drive array is a set of hard disk drives or physical drives grouped together as a single, larger drive. An array is comprised of one or more subsets called logical drives (or logical volumes) that are spread across all physical drives in the array.