[FAQ] Raid Configurations

[KevinN]

Redundant Array of Independent (or inexpensive) disks, a method to increase the safety of storage in a disk system. Multiple disks cooperate and are seen as one by the system via a special controller. By having the data (disk mirroring) onto multiple disks at once (redundancy) it achieves a higher grade of security. Disk stripping is also used. There are several levels of RAID with different grades of redundancy (short description):

 

 

 

RAID 0 - Disk striping which divides the data on multiple physical disk units.

RAID 1 - Disk mirroring which consists of two disks who stores identical parrarel data.

RAID 2 - Divides the data sections between multiple disk units where some of the units are for storage of error handling codes.

RAID 3 - Uses the same section breakdown method as RAID 2, but one disk unit in the group is for storing (parity data(translation?)

RAID 4 - Pretty much identical with raid 3, but using a larger data striping. RAID 4 does not give any major advantage over RAID 3, and is rarely used.

RAID 5 - Is not using a special (parity data(translation?) as RAID 4. Every unit in the array stores sequentially the parity information to different sets of strips.

RAID 6 - Enhances fault tolerance of RAID 5 by adding yet another parity unit.

RAID 10 - Uses both the advantages from RAID 0 and RAID 1 and is often called RAID 0+1.

RAID 53 - A combination of RAID 0 and RAID 3. Incoming data is shredded between two RAID 3 arrays.

 

Redundancy

Using multiple sets of the same data or devices to ensure safety or function. Data Storage Systems like RAID is based on a redundant system.

 

I hope someone finds this useful!

 

Happy reading!

Edited May 7, 2012 by KevinN