HP A7143A RAID160 SA Controller Support Guide

RAID Technology Overview

HP RAID160 SA Controller Supported RAID Configurations

Chapter 1 21

• Only 50% of total disk drive capacity is usable for data storage

RAID 1+0—Disk Drive Mirroring and Striping

This configuration requires an array with four or more physical disks.

The disks are mirrored in pairs and data blocks are striped across the

mirrored pairs (see Figure 1-6, “Mirroring and Striping (RAID 1+0),”

Figure 1-6 Mirroring and Striping (RAID 1+0)

In each mirrored pair, the physical disk that is not busy answering other

requests answers any read request sent to the array (this behavior is

called load balancing). If a physical disk fails, the remaining disk in the

mirrored pair can still provide all the necessary data. Several disks in

the array can fail without incurring data loss, as long as no two failed

disks belong to the same mirrored pair.

This fault-tolerance method is useful when high performance and data

protection are more important than the cost of physical disks.

Advantages

• Highest read and write performance of any fault-tolerant

configuration

• No loss of data as long as none of failed disks are mirrored to another

failed disk (up to half of the physical disks in the array can fail)