• RAID (Redundant Array of Independent Disks) is a data storage virtualization technology that combines multiple physical disk drive components into a single logical unit for the purposes of data redundancy, performance improvement, or both.

• Data is distributed across the drives in one of several ways, referred to as RAID levels, depending on the required level of redundancy and performance.

• The different schemas, or data distribution layouts, are named by the word RAID followed by a number, for example RAID 0 or RAID 1.

• Each schema, or a RAID level, provides a different balance among the key goals: reliability, availability, performance, and capacity.

• RAID levels greater than RAID 0 provide protection against unrecoverable sector read errors, as well as against failures of whole physical drives.

RAID level descriptions: