RAID - What is it?
RAID, an acronym for redundant array of independent disks, is a technology that provides increased storage reliability through redundancy, combining multiple low-cost, less-reliable disk drives components into a logical unit where all drives in the array are interdependent. This concept was first defined by David A. Patterson, Garth A. Gibson, and Randy Katz at the University of California, Berkeley in 1987 as redundant array of inexpensive disks. Marketers representing industry RAID manufacturers later reinvented the term to describe a redundant array of independent disks as a means of dissociating a low-cost expectation from RAID technology.
RAID is now used as an umbrella term for computer data storage schemes that can divide and replicate data among multiple disk drives. The schemes or architectures are named by the word RAID followed by a number (e.g., RAID 0, RAID 1). The various designs of RAID systems involve two key goals: increase data reliability and increase input/output performance. When multiple physical disks are set up to use RAID technology, they are said to be in a RAID array. This array distributes data across multiple disks, but the array is addressed by the operating system as one single disk. RAID can be set up to serve several different purposes