Chapter 1 Overview
1.2 Configuration
ETERNUS DX60/DX80/DX90 Disk storage system User Guide
31
Copyright 2011 FUJITSU LIMITED
P3AM-3042-08ENZ0
Table 1.2
Formula for calculating user capacity for each RAID level
*1:
Actual number of disks can be installed depend on the models.
■
Reliability, performance, capacity for each RAID level
shows the comparison result of reliability, performance, capacity for each RAID level.
Table 1.3
User capacity for each RAID level
*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.
RAID level
Number of disks
(*1)
Formula for user capacity computation
RAID0
2 to 16
Disk capacity
×
Number of disks
RAID1
2
Disk capacity
×
Number of disks/2
RAID1+0
4 to 32
Disk capacity
×
Number of disks/2
RAID5
3 to 16
Disk capacity
×
(Number of disks - 1)
RAID5+0
6 to 32
Disk capacity
×
(Number of disks - 2)
RAID6
5 to 16
Disk capacity
×
(Number of disks - 2)
RAID level
Reliability
Performance
(Writing speed)
(*1)
Capacity
RAID0
Bad
Very Good
Very Good
RAID1
Good
Good
Not Bad
RAID1+0
Good
Very Good
Not Bad
RAID5
Good
Good
Good
RAID5+0
Good
Good
Good
RAID6
Very Good
Good
Good