•
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.
•
For RAID5, RAID5+0, and RAID6, ensure that a single RAID group is not being configured with too many
drives.
If the number of drives increases, the time to perform data restoration from parities and Rebuild/Copyback
when a drive fails also increases.
For details on the recommended number of drives, refer to
.
•
The RAID level that can be registered in REC Disk Buffers is RAID1+0. The drive configurations that can be
registered in REC Disk Buffers is 2D+2M or 4D+4M.
For details on the Thin Provisioning function and the RAID configurations that can be registered in Thin Pro-
visioning Pools, refer to
"Storage Capacity Virtualization" (page 43)
For details on the Flexible Tier functions and the RAID configurations that can be registered in Flexible Tier
Pools, refer to
"Automated Storage Tiering" (page 49)
An assigned CM is allocated to each RAID group. For details, refer to
For the installation locations of the drives that configure the RAID group, refer to
.
Volume
This section explains volumes.
Logical drive areas in RAID groups are called volumes.
A volume is the basic RAID unit that can be recognized by the server.
Figure 9 Volume Concept
RAID group 1
RAID group 2
Volume 1
Volume 2
Volume 3
A volume may be up to 128TB. However, the maximum capacity of volume varies depending on the OS of the
server.
The maximum number of volumes that can be created in the ETERNUS DX is 16,384. Volumes can be created
until the combined total for each volume type reaches the maximum number of volumes.
A volume can be expanded or moved if required. Multiple volumes can be concatenated and treated as a single
volume. For availability of expansion, displacement, and concatenation for each volume, refer to
umes of Each Function" (page 212)
.
2. Basic Functions
RAID Functions
26
FUJITSU Storage ETERNUS DX500 S4/DX600 S4, ETERNUS DX500 S3/DX600 S3 Hybrid Storage Systems Design Guide (Basic)
Copyright 2019 FUJITSU LIMITED
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