Raid Groups; Figure 4.7 Example Of A Raid Group; Table 4.2 Recommended Number Of Drives Per Raid Group - Fujitsu ETERNUS DX80 S2 Overview

Chapter 4 System Configuration

4.2 RAID Groups

4.2 RAID Groups
This section explains RAID groups.
A RAID group is a group of drives. It is a unit that configures RAID. Multiple RAID groups with the same RAID
level or multiple RAID groups with different RAID levels can be set together in the ETERNUS DX Disk storage
system. After a RAID group is created, RAID levels can be changed and drives can be added.
The same size drives (2.5", 3.5") and the same kind of drives (SAS, Nearline SAS, SLC type SSD, MLC type SSD,
or SED) must be used to configure a RAID group.

Figure 4.7 Example of a RAID group

SAS
600GB
Table 4.2 shows the recommended number of drives that configure a RAID group.
Table 4.2 Recommended number of drives per RAID group
RAID level
RAID1
RAID1+0
RAID5
RAID5+0
RAID6
*1: D = Data, M = Mirror, P = Parity
• Sequential access performance hardly varies with the number of drives for the RAID group.
• Random access performance tends to be proportional to the number of drives for the RAID group.
• Use of higher capacity drives will increase the time required for the drive rebuild process to complete.
• The higher the number of drives in a RAID5, RAID5+0, or RAID6 configuration, the longer the period of
time for data restoration and rebuilding processes from parities.
• To use the Thin Provisioning function or the Flexible Tier function, the drive area of the virtual volume is
managed using a pool.
The following table shows the RAID configurations that can be registered in a Thin Provisioning Pool or a
Flexible Tier Pool.
SAS SAS SAS
600GB 600GB 600GB
RAID group 1
Number of configuration drives
2
4 to 32
3 to 16
6 to 32
5 to 16
ETERNUS DX80 S2/DX90 S2 Disk storage system Overview
Copyright 2013 FUJITSU LIMITED
SAS SSD
600GB 200GB
Recommended number of drives (*1)
2(1D+1M)
4(2D+2M), 6(3D+3M), 8(4D+4M), 10(5D+5M)
3(2D+1P), 4(3D+1P), 5(4D+1P), 6(5D+1P)
3(2D+1P) × 2, 4(3D+1P) × 2, 5(4D+1P) × 2, 6(5D+1P) × 2
5(3D+2P), 6(4D+2P), 7(5D+2P)
37
SSD SSD SSD
200GB 200GB 200GB
RAID group 2
P3AM-4812-11ENZ0