2. M310 Component Selection (14)
(4-5) Supported RAID
NEC Storage M-Series supports the following RAID types. (Note: Only RAID-1, 10, 5/50(4+P),
6/60(4+PQ), 6/60(8+PQ) are supported with SSD)
(4-6) Dynamic Pool
NEC Storage M-Series supports only dynamic pools. LUN capacity can be modified dynamically.
Capacity is constant regardless of the number of disk drives. It is slightly less than the table above.
Striping is automatic when an applicable number of disk drives are used with RAID types that support it.
<Example> RAID-1 with 4 disk drives is automatically configured as RAID-10.
Refer to “5. Functions <Pool>” for more details about dynamic pool.
*
RAID-0: Data is not protected.
RAID Type
Configuration
Number of physical disk drives
Redundancy
RAID Capacity
RAID-0
*
None
Physical disk capacity x 1
RAID-1/10
(1+1) x n
2 or more disk drives
1
Physical disk capacity x 1/2
RAID-5/50
(2+P) x n
3 or more disk drives
1
Physical disk capacity x 2/3
(4+P) x n
5 or more disk drives
1
Physical disk capacity x 4/5
(8+P) x n
9 or more disk drives
1
Physical disk capacity x 8/9
RAID-6/60
(4+PQ) x n
6 or more disk drives
2
Physical disk capacity x 2/3
(8+PQ) x n
10 or more disk drives
2
Physical disk capacity x 4/5
RAID-TM
(1+1+1) x n
3 or more disk drives
2
Physical disk capacity x 1/3
(4-4) Disk Drive Usage
Both the base unit and SAS disk enclosures can include a mix of SAS disk drives/NL-SAS disk
drives/SAS SSD and disk drives with different capacities and rotation speeds.
A pool must contain disk drives with the same interface. The capacity or rotation speed does not matter.
However, it is strongly recommended to use devices of the same capacity and same rotation speed in
a pool. When using different capacities of disk drive in a pool, the pool will be created based on the
disk drive with the smallest capacity. In this case, the rest of larger disk drives are not available.
Since SAS and Nearline SAS are regarded as different interfaces, it is impossible to mix SAS and
Nearline SAS in same pool. Also mix of HDD and SSD, mix of self-encrypting HDD and non-encrypting
HDD is not available in same pool. For SSD, It is recommended to mix same SSD type and same
capacity.
<Example>
A pool configured by SAS disk drives (15krpm/300GB) and SAS disk drives (15krpm/600GB)
Ø
The SAS disk drive (15krpm/600GB) is treated as a SAS disk drive (15krpm/300GB).
When using different speeds of disk drives in a pool, the pool will be created based on the slowest disk
speed. In this case, performance will not be as good as expected because drives with faster speed are
treated the same as drives with the slowest speed.
<Example>
A pool configured by 3.5” SAS disk drives (15krpm/600GB) and 2.5” SAS disk drive(10krpm/600GB)
Ø
The SAS disk drive (15krpm/600GB) is treated as a SAS disk drive (10krpm/600GB).
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