What is RAID (Redundant Array of Inexpensive disks)? Explain its level?

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RAID is a mechanism of storing the same data in different locations. Since the same data is stored, it is termed as redundant. The data is stored on multiple disks which improves performance. The drive's storage is divided into units ranging from a sector (512 bytes) up to several megabytes. This is termed as disk stripping.

There are NINE types of RAID plus an additional non-redundant array (RAID-0). However, RAID levels 0, 1, and 5 are the most commonly found.

► RAID 0: This level does involve stripping but no redundancy of data. Offers the best performance at the cost of NO fault tolerance.
► RAID 1: This level is termed as data mirroring consisting of at least two drives that duplicate the storage of data. No stripping involved. Often used for multi user system for best performance and fault tolerance.
► RAID 2: It involves stripping with some disks storing error checking and correcting (ECC) information.
► RAID 5: Consists of 3 or more disks in a way that protects data against loss of any one disk.
► RAID 6: Has stripped disks with dual parity.
► RAID 10: uses both striping and mirroring.
► RAID 53: Merges the features of RAID level 0 and RAID level 3
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