RAID configurations explained

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Raid is an acronym for Redundant Array of Independent Disks or Redundant Array of Inexpensive disks. Raid uses multiple disks to increase performance or fault tolerance. In general, fault tolerance refers to the system that can suffer a fault, but can still tolerate the error and continue to operate.


Both software and hardware RAID are available. In software-based RAID, the operating system manages the RAID configuration. Hardware-based RAID is supported on some motherboards and you can also purchase external hardware based arrays.

Common types of RAID configurations


This type of RAID involves two or more disks. In other words, this RAID configuration is known as stripped volume. This raid provide increase in writing and reading performance, but does not provide fault tolerance. This is because the data will be broken into two parts and each part will be written into separate disk. In case of a disk failure the data will be corrupted because the other end of the data will be in the failed disk. This raid configuration is only good when write and read performance is the priority and not fault tolerance.



This type of RAID involves two disk only and is commonly known as mirrored volume. In this RAID configuration the same data will be written into each hard disks separately. So the same data will be available in two separate disk. This RAID configuration is the best if fault tolerance is a priority and not read and write performance. Because, if one disk fail the same data will be available in the working disk.


RAID-5 uses at least three disks and is commonly called stripping with parity. It uses the equivalent of one drives as parity to provide fault tolerance. In RAID-5, you will always have at least three drives, and the equivalent of one drive is used for parity. When a RAID-5 array writes data to a drive, it calculates the parity bit and writes it along with the data.


Raid 10 is a combination of RAID-1 (mirror) and RAID-0 (striped). It's often referred as stripe of mirrors and includes at least four disks. This is one of the best RAID configuration, but is more expensive. This configuration is often used in a server environment. This configuration provides fault tolerance and write and read performance. At the top of this RAID configuration is the stripped raid, which means data is broken into two parts and written into an array of two disks, which is RAID-1 (mirrored) so the same half of the data will be available in two disks. This provide read and write speed and also provide fault tolerance.