RAID is an acronym for Redundant Array of Independent Disks. It involves a set of strategies to improve system performance and increase fault tolerance. Generally, two or more drives are combined to achieve this. RAID also provides better reliability and bigger data volume sizes. This is because RAID places data across a number of disks, which the Operating System sees as just one disk.

RAID has several levels. Some of the most common are the following:

First is RAID 0. In this RAID level, pieces of data are broken into smaller fragments as they are being written to the disk. The fragments are written to drives within the same sector. This structure allows RAID 0 to offer a larger bandwidth. However, the drawback in using RAID 0 is that one disk failure will destroy the whole array.

RAID 1 is another level of RAID. This level uses the process of mirroring to write data to the disks. It incorporates features for fault tolerance, which enables the entire array to remain efficient as long as one disk is functioning properly. RAID 1 is relatively more costly than the previous level because it requires more disks for data storage.

The next level is RAID 2. To enhance its error correction features, RAID 2 utilizes Hamming Codes. RAID 2 entails the synchronization of multiple parity disks.

RAID 3, on the other hand, uses dedicated parity disks. By using this type of disks, RAID 3 ensures that processes will continue even if the parity drive stops during operation.

The above RAID levels can be merged together to form nested RAID levels. Experts believe that doing this can greatly improve system performance.