LSI SAS2 Overview of Integrated RAID Mirrored Volumes, Introduction, Types of mirrored arrays

SAS2 Integrated RAID Solution User Guide Chapter 2: Overview of Integrated RAID Mirrored Volumes Introduction

Chapter 2

Overview of Integrated RAID Mirrored Volumes

This chapter provides an overview of the LSI Integrated RAID features that support the creation of mirrored arrays.

2.1 Introduction	As a result of the shift towards network-attached storage (NAS), Internet service
	providers need a cost-effective, fault-tolerant solution to protect the operating systems
	on small form-factor, high-density, rack-mountable servers. The mirroring features of
	the LSI Integrated RAID solution provide data protection for the system boot volume,
	which safeguards the operating system and other critical information on servers and
	high-performance workstations. The Integrated RAID solution supports the following
	types of mirrored arrays:
	 The Integrated Mirroring solution, which provides features of RAID 1
	 The Integrated Mirroring + Striping solution, which provides features of RAID 10

2.2Integrated Mirroring and Integrated Mirroring Enhanced Features

The Integrated Mirroring Enhanced solution, which provides features of RAID 1 Enhanced (RAID 1E)

These three mirroring solutions provide a robust, high-performance, fault-tolerant solution to data storage needs at a lower cost than a dedicated RAID controller.

Mirrored volumes may have from two-to-ten disks to provide fault-tolerant protection for critical data. Mirrored volumes also support one or two global hot spare drives, with a maximum of 14 drives on each LSI SAS2 controller.

NOTE: Fourteen drives is the theoretical upper limit for a single LSI SAS2 controller, although the controller itself may support fewer than 14 drives. You can also configure one mirrored volume and one Integrated Striping volume on the same LSI SAS controller.

Each SAS2 controller can have two global hot spare disks available to automatically replace a failed disk in the one or two mirrored volumes configured on the controller. The hot spares make the mirrored volumes even more fault-tolerant.

Integrated Mirroring, Integrated Mirroring + Striping, and Integrated Mirroring Enhanced volumes support the following features:

Configurations of one or two mirrored volumes on each LSI SAS2 controller. Each volume can consist of two mirrored disks for an Integrated Mirroring volume; three-to-ten mirrored disks for an Integrated Mirroring Enhanced volume; or four, six, eight, or ten mirrored disks for an Integrated Mirroring + Striping volume.

(Optional) Two global hot spare disks per LSI SAS2 controller to automatically replace failed disks in mirrored volumes.

LSI Corporation Confidential August 2010 Page 7