Summary of RAID Levels

RAID Level

Description  

Minimum Number of Drives Required

Maximum Number of Drives Supported

Data
Reliability

Data
Transfer Rates

0

Striping of data across multiple drives in an array. This is a high performance solution. However there is no data protection.

2

4 (if controller supports 2 channels)


8 (if controller supports 4 channels)

No data protection.

Very High

1

Also known as mirroring. Mirroring refers to the 100% duplication of data from one disk to another. This is a high availability solution, but due to the 100% duplication, it is also a costly storage solution.

2

2

Highest reliability; much higher reliability than a single drive (no RAID).

Reads are the same as a single drive.
Writes are about two times of a single drive.

0/1

Mirrored striping need  4 disks.

4

4

Same reliability as RAID 1; higher reliability than a single drive or RAID 0.

Reads are similar to RAID 0.  Writes are about two times of RAID 0.

 

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