Selecting A Raid Level And Tuning Performance; Supported Raid Levels - IBM ServeRAID User Reference

Selecting a RAID level and tuning performance

Disk arrays are used to improve performance and reliability. The amount of
improvement depends on the application programs that you run on the server and
the RAID levels that you assign to the logical drives.
Each RAID level provides different levels of fault-tolerance (data redundancy),
utilization of physical drive capacity, and read and write performance. In addition,
the RAID levels differ in regard to the minimum and maximum number of physical
drives that are supported.
When selecting a RAID level for your system, consider the following factors.
RAID level Data
redundancy
RAID level-0 No
RAID level-1 Yes
RAID level-1E Yes
RAID level-5 Yes
RAID level-5E Yes
RAID level-00 No
RAID level-10 Yes
RAID Yes
level-1E0
RAID level-50 Yes
Physical drive utilization, read performance, and write performance depend on the
number of drives in the array. Generally, the more drives in the array, the better the
performance.

Supported RAID levels

The ServeRAID controllers support RAID level-0, level-1, level-1E, level-5, level-5E,
level-00, level-10, level-1E0, and level-50.
The integrated RAID controllers support RAID level-1 only. The ServeRAID-5i
controller does not support RAID level-5E.
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IBM ServeRAID: User's Reference, Version 5.10
Physical drive Read
capacity performance
utilization
100% Superior
50% Very high
50% Very high
67% to 94% Superior
50% to 88% Superior
100% Superior
50% Very high
50% Very high
67% to 94% Superior
Write Built-in
performance spare
drive
Superior No
Very high No
Very high No
High No
High Yes
Superior No
Very high No
Very high No
High No
Min. Max.
number number
of drives of drives
1 16
2 2
3 16
3 16
4 16
2 60
4 60
6 60
6 60