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2. Basic Functions
RAID Functions
■
Recommended RAID Level
Recommended RAID levels are RAID5 and RAID6.
For SSDs, a RAID5 configuration or a fault tolerant enhanced RAID6 configuration is recommended because SSDs
operate much faster than other types of drive. For large capacity SSDs, using a RAID6-FR configuration, which
provides excellent performance for the rebuild process, is recommended.
User Capacity (Logical Capacity)
User Capacity for Each RAID Level
The user capacity depends on the capacity of drives that configure a RAID group and the RAID level.
Table 6
shows the formula for calculating the user capacity for each RAID level.
Table 6
Formula for Calculating User Capacity for Each RAID Level
RAID level
RAID0
RAID1
RAID1+0
RAID5
RAID5+0
RAID6
RAID6-FR
*1: "N" is the number of RAID6 configuration sets. For example, if a RAID6 group is configured with "(3D+2P)´2+1HS", N is "2".
User Capacity of Drives
Table 7
shows the user capacity for each drive.
Table 7
User Capacity per Drive
Product name (*1)
960GB SSD
1.92TB SSD
3.84TB SSD
7.68TB SSD
15.36TB SSD
30.72TB SSD
*1: The capacity of the product names for the drives is based on the assumption that 1MB = 1,000
drive is based on the assumption that 1MB = 1,024
capacity.
The user capacity is constant regardless of the encryption support (SED).
Formula for user capacity calculation
Drive capacity ´ Number of drives
Drive capacity ´ Number of drives ¸ 2
Drive capacity ´ Number of drives ¸ 2
Drive capacity ´ (Number of drives - 1)
Drive capacity ´ (Number of drives - 2)
Drive capacity ´ (Number of drives - 2)
Drive capacity ´ (Number of drives - (2 ´ N) - Number of hot spares) (*1)
User capacity
914,432MB
1,830,144MB
3,661,568MB
7,324,416MB
14,650,112MB
29,301,504MB
2
bytes. Furthermore, OS file management overhead will reduce the actual usable
24
2
bytes, while the user capacity for each
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