# 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 | Physical drive capacity utilization | Read performance | Write performance | Built-in spare drive | Min. number of drives | Max. number of drives
--- | --- | --- | --- | --- | --- | --- | ---
RAID level-0 | No | 100% | Superior | Superior | No | 1 | 16
RAID level-1 | Yes | 50% | Very high | Very high | No | 2 | 2
RAID level-1E | Yes | 50% | Very high | Very high | No | 3 | 16
RAID level-5 | Yes | 67% to 94% | Superior | High | No | 3 | 16
RAID level-5E | Yes | 50% to 88% | Superior | High | Yes | 4 | 16
RAID level-5EE | Yes | 50% to 88% | Superior | High | Yes | 4 | 16
RAID level-00 | No | 100% | Superior | Superior | No | 2 | 60
RAID level-10 | Yes | 50% | Very high | Very high | No | 4 | 60
RAID level-1E0 | Yes | 50% | Very high | Very high | No | 6 | 60
RAID level-50 | Yes | 67% to 94% | Superior | High | No | 6 | 60

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.

## More information

- Understanding RAID technology
- Understanding creating logical drives
- Selecting the logical drive size
- Selecting the RAID level by array capacity
- Example: Logical drive configurations
- Creating logical drives (action)
- Configuring RAID and creating arrays (action)
- Creating logical drives in the wizard
- Things to consider when changing the RAID level

Glossary | Contents

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