The RAID is an acronym for Redundant Array of Inexpensive (or Independent) Disks.  RAID is a method of combining multiple hard drives into one logical entity (grouping two or more hard drives so that they appear as one device to the host system). RAID technology was developed to overcome the fault tolerance and performance limitations of traditional hard disk storage. It can provide fault tolerance and higher throughput than a single disk or group of independent disks. Once considered a complex and relatively specialized storage solution, arrays are now easy to use and essential for a wide range of client/server applications.