User guide

Chapter 1 Overview
> 1.2 Configuration
ETERNUS DX60/DX80/DX90 Disk storage system User Guide
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Copyright 2010 FUJITSU LIMITED
P3AM-3042-06ENZ0
1.2.2 RAID Groups and Volumes
■ RAID group
In an ETERNUS DX60/DX80/DX90 Disk storage system, you can set up the RAID groups to all
use the same RAID level or a mixture of different RAID levels.
Figure 1.7 Example of a RAID group
Table 1.4
show the recommended number of disks that configures a RAID group.
Table 1.4 Recommended number of disks per RAID group
■ Volume
Logical disk areas in RAID groups are called volumes.
A volume is the basic RAID unit, that can be recognized by the server.
Figure 1.8 RAID group concept
RAID level Recommended number of disks
RAID1 2
RAID1+0 4, 6, 8, 10
RAID5 3, 4, 5, 6
RAID5+0 6, 8, 10, 12
RAID6 5, 6, 7
• Adding more disks to a RAID group improves performance.
• Use of higher capacity disks in a RAID group will increase the time
required for the disk rebuild process to complete.
• The more disks per RAID5, RAID5+0, or RAID6 group, the longer the
period of time for data restoration from parities and rebuilding process.
RAID Group 1
RAID Group 2
RAID Group 1 RAID Group 2
Volume 1
Volume 2
Volume 3