RAID (redundant array of independent disks, originally redundant array of inexpensive disks) is a storage technology that combines multiple disk drive components into a logical unit. Data is distributed across the drives in one of several ways called “RAID levels”, depending on the level of redundancy and performance required. The term “RAID” was first defined by David Patterson, Garth A. Gibson, and Randy Katz at the University of California, Berkeley in 1987.