RAID stands for Redundant Array of Inexpensive (Independent) Disks.

On most situations you will be using one of the following four levels of RAIDs.

  • RAID 0

  • RAID 1

  • RAID 5

  • RAID 10 (also known as RAID 1+0)

This article explains the main difference between these raid levels along with an easy to understand diagram.

In all the diagrams mentioned below:

  • A, B, C, D, E and F – represents blocks

  • p1, p2, and p3 – represents parity

RAID LEVEL 0

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Following are the key points to remember for RAID level 0.

  • Minimum 2 disks.

  • Excellent performance ( as blocks are striped ).

  • No redundancy ( no mirror, no parity ).

  • Don’t use this for any critical system.

RAID LEVEL 1

Following are the key points to remember for RAID level 1.

  • Minimum 2 disks.

  • Good performance ( no striping. no parity ).

  • Excellent redundancy ( as blocks are mirrored ).

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Following are the key points to remember for RAID level 1.

  • Minimum 2 disks.

  • Good performance ( no striping. no parity ).

  • Excellent redundancy ( as blocks are mirrored ).

RAID LEVEL 5

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Following are the key points to remember for RAID level 5.

  • Minimum 3 disks.

  • Good performance ( as blocks are striped ).

  • Good redundancy ( distributed parity ).

  • Best cost effective option providing both performance and redundancy. Use this for DB that is heavily read oriented. Write operations will be slow.

RAID LEVEL 10

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Following are the key points to remember for RAID level 10.

  • Minimum 4 disks.

  • This is also called as “stripe of mirrors”

  • Excellent redundancy ( as blocks are mirrored )

  • Excellent performance ( as blocks are striped )

  • If you can afford the dollar, this is the BEST option for any mission critical applications (especially databases).