Table 1.2 Formula For Calculating User Capacity For Each Raid Level; Table 1.3 User Capacity For Each Raid Level - Fujitsu Eternus DX60 User Manual

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.
Formula for calculating user capacity for each RAID level
Number of disks
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
ETERNUS DX60/DX80/DX90 Disk storage system User Guide
Copyright 2011 FUJITSU LIMITED
Formula for user capacity computation
(*1)
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
(*1)
(Writing speed)
Very Good
Good
Very Good
Good
Good
Good
31
Capacity
Very Good
Not Bad
Not Bad
Good
Good
Good
P3AM-3042-08ENZ0