Fujitsu Eternus DX60 User Manual page 31

Chapter 1 Overview
> 1.2 Configuration
Table 1.2
RAID level
RAID0
RAID1
RAID1+0
RAID5
RAID5+0
RAID6
*1: Actual number of disks can be installed depend on the models.
Reliability, performance, capacity for each RAID level
Table 1.3
Table 1.3
RAID level
RAID0
RAID1
RAID1+0
RAID5
RAID5+0
RAID6
*1: Performance may differ according to the number of disks and the processing method from the host.
Recommended RAID level
Select the appropriate RAID level according to the usage.
• Recommended RAID level is RAID1, RAID1+0, RAID5, RAID5+0 and RAID6.
• For read and write performance, RAID1+0 configuration is recommended.
• For read only file servers and backup servers, RAID5, RAID5+0, or RAID6 can also be used.
However, if the disk fails, note that data restoration from parities and rebuilding process may
result in a loss in performance.
P3AM-3042-06ENZ0 ETERNUS DX60/DX80/DX90 Disk storage system User Guide
Formula for calculating user capacity for each RAID level
Number of disks (*1)
2 to 16
2
4 to 32
3 to 16
6 to 32
5 to 16
shows the comparison result of reliability, performance, capacity for each RAID level.
User capacity for each RAID level
Reliability
Bad
Good
Good
Good
Good
Very Good
Formula for user capacity computation
Disk capacity × Number of disks
Disk capacity × Number of disks/2
Disk capacity × Number of disks/2
Disk capacity ×
(Number of disks - 1)
Disk capacity ×
(Number of disks - 2)
Disk capacity ×
(Number of disks - 2)
Performance
(Writing speed) (*1)
Very Good
Good
Very Good
Good
Good
Good
31
Capacity
Very Good
Not Bad
Not Bad
Good
Good
Good
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