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Chapter 2 Overview of Disk Array Configuration Setting
I-26
(1) You can bind a dynamic pool:
You can bind a virtual storage space, or a dynamic pool, by selecting a set of unused physical
disks on the disk array. The RAID type usable and the number of physical disks required for a
dynamic pool are fixed. Select either of the following two types of RAID6 configuration
according to the number of physical disks required. The two types of configuration have
different capacity efficiencies:
RAID6 (4+PQ): 6 or more physical disks required (capacity efficiency: 67% approx.)
RAID6 (8+PQ): 10 or more physical disks required (capacity efficiency: 80%)
For details on how to bind a dynamic pool, refer to 7.1.1 “Binding a Pool” in Part IV
“Operations”.
y Dynamic pool
RAID Type
Disk Array Number of Physical Disks
RAID6 (4+PQ) 6 to 60
(120 or 240)*1
RAID6 (8+PQ)
S400/S1400/
S2400/S2800
10 to 60
(120 or 240)*1
*1: The maximum number of physical disks is 60 when pools are in use.
To use 61 or more disks, you need to add physical disks by extending dynamic pools.
(2) You can expand the dynamic pool capacity:
You can expand the capacity of the dynamic pool by selecting unused physical disks on the disk
array and putting them into the dynamic pool. The capacity actually added is the capacity of the
additional physical disk(s) multiplexed by the pool capacity efficiency. You can add physical
disks one by one. Naturally, you can add multiple physical disks at one time.
Usually, expanding the dynamic pool rebuilds data on the additional physical disk(s) to keep the
redundancy of RAID. Rebuilding data puts some load to the physical disks of the dynamic pool
and influences access to the existing logical disks which belong to the pool. The additional
space becomes available after the rebuild process finishes.
However, when the number of physical disks simultaneously added to the pool is a specified
number or more, the dynamic pool is expanded and made available without the rebuild process.
The additional space is usable immediately after the physical disks are added to the pool.
The RAID configuration cannot be changed from RAID6 (4+PQ) to RAID6 (8+PQ) or vise versa.
You need to add physical disks to the pool, keeping the RAID configuration.