Fujitsu ETERNUS DX100 S3 - Logical Device Expansion; Figure 31 Logical Device Expansion (When Expanding the RAID Group Capacity); Figure 32 Logical Device Expansion (When Changing the RAID Level)

Logical Device Expansion
Logical Device Expansion (LDE) allows the capacity of an existing RAID group to be dynamically ex-
panded by changing of the RAID level or the drive configuration of the RAID group. When this
function is performed, drives can be also added at the same time. By using this LDE function to ex-
pand the capacity of an existing RAID group, a new volume can be added without having to add
new RAID groups.
•
Expand the RAID group capacity (from RAID5(3D+1P) g
RAID5(5D+1P))
Figure 31 Logical Device Expansion (When Expanding the RAID Group Capacity)
RAID5 (3D+1P) 600GB x 4
LUN0
Unused 600GB x 2
RAID5 (5D+1P) 600GB x 6
Expansion
LUN0
Expands the capacity
by adding two drives
•
Change the RAID levels (from RAID5(3D+1P) g RAID1+0(4D+4M))
Figure 32 Logical Device Expansion (When Changing the RAID Level)
RAID5 (3D+1P) 600GB x 4
LUN0
Unused 600GB x 4
RAID1+0 (4D+4M) 600GB x 8
Expansion
LUN0
LUN0
E
xpands the capacity by
adding four drives and
changes the RAID level
LDE works in terms of RAID group units. If a target RAID group contains multiple volumes, all of the
data in the volumes is automatically redistributed when LDE is performed. Note that LDE cannot be
performed if it causes the number of data drives to be reduced in the RAID group.
In addition, LDE cannot be performed for RAID groups in which the following conditions apply.
•
RAID groups that belong to TPPs or FTRPs
•
The RAID group that is registered as an REC Disk Buffer
•
RAID groups in which volumes are not registered
•
RAID groups in which WSVs are registered
•
RAID groups that are configured with RAID5+0 or RAID6-FR
2. Basic Functions
Optimization of Volume Configurations
59
Fujitsu Storage ETERNUS DX100 S4/DX200 S4, ETERNUS DX100 S3/DX200 S3 Hybrid Storage Systems
Design Guide (Basic)
Copyright 2023 Fujitsu Limited
P3AM-7642-32ENZ0