IT: Redundant Array of Independent Disks/RAID (Definitions)

"Installation of several disk drives to a system. Some drives contain mirrored information so data is not lost. RAID disk drives can be replaced quickly in cases of disk failure. This technology is good for Web and database servers, so that no information is lost and the information is always available." (Patrick Dalton, "Microsoft SQL Server Black Book", 1997)

"Sometimes referred to as redundant array of inexpensive disks, a system that uses multiple disk drives (an array) to provide performance and reliability. There are six levels describing RAID arrays, 0 through 5. Each level uses a different algorithm to implement fault tolerance." (Microsoft Corporation, "SQL Server 7.0 System Administration Training Kit", 1999)

"A disk system that comprises multiple disk drives (an array) to provide higher performance, reliability, storage capacity, and lower cost. Fault-tolerant arrays are categorized in six RAID levels: 0 through 5. Each level uses a different algorithm to implement fault tolerance." (Thomas Moore, "EXAM CRAM™ 2: Designing and Implementing Databases with SQL Server 2000 Enterprise Edition", 2005)

"A specific fault-tolerant disk array system design strategy that takes into account issues of cost benefit, reliability, and performance. It can be implemented at a hardware or a software level; each provides a different profile of cost, reliability, and performance. Depending on the person defining RAID, the word independent may be substituted with inexpensive." (Allan Hirt et al, "Microsoft SQL Server 2000 High Availability", 2004)

"A bunch of small, cheap disks. A RAID array is a group of disks used together as a single unit logical disk. RAID arrays can help with storage capacity, recoverability and performance, using what are called mirroring and striping. Mirroring creates duplicate copies of all physical data. Striping breaks data into many small pieces, where those small pieces can be accessed in parallel." (Gavin Powell, "Beginning Database Design", 2006)

"A schema for using groups of disks to increase performance, protect data, or both." (Tom Petrocelli, "Data Protection and Information Lifecycle Management", 2005)

"This is a grouping, or array, of hard disks that appear as a single, logical drive to the operating system." (Joseph L Jorden & Dandy Weyn, "MCTS Microsoft SQL Server 2005: Implementation and Maintenance Study Guide - Exam 70-431", 2006)

"RAID is an acronym for Redundant Array of Independent Disks. RAID is a collection of disks that operates as a single disk." (S. Sumathi & S. Esakkirajan, "Fundamentals of Relational Database Management Systems", 2007)

"A RAID array uses multiple physical disks to simulate one logical, larger disk, often with protection from disk failure. (The I can also stand for Independent, and the D can also stand for Drives.) " (Victor Isakov et al, "MCITP Administrator: Microsoft SQL Server 2005 Optimization and Maintenance (70-444) Study Guide", 2007)

"Using more disks than is necessary for the actual data itself, as a buffer against failure of one (or possibly more) disks." (David G Hill, "Data Protection: Governance, Risk Management, and Compliance", 2009)

"A category of disk drives that employ two or more drives in combination for fault tolerance and performance." (Martin Oberhofer et al, "The Art of Enterprise Information Architecture", 2010)

"A system of disk storage where data is distributed across several drives for faster access and improved fault tolerance." (Paulraj Ponniah, "Data Warehousing Fundamentals for IT Professionals", 2010)

"A technology for configuring a logical data storage device across multiple physical devices to improve performance, availability or both. The primary goal is fault tolerance as in most configurations data can be recovered after a device failure and in some cases, without interruption." (DAMA International, "The DAMA Dictionary of Data Management", 2011)

"An acronym that means Redundant Array of Independent Disks. RAID is used to provide balance between performance and fault tolerance. RAID systems use multiple disks to create virtual disks (storage volumes) formed by several individual disks. RAID systems provide performance improvement and fault tolerance." (Carlos Coronel et al, "Database Systems: Design, Implementation, and Management" 9th Ed., 2011)

"A category of disk drives that employ two or more drives in combination to deliver fault tolerance and improved performance." (Craig S Mullins, "Database Administration", 2012)

"A multi-disk storage system that optimizes performance, data safety, or both, depending on the type." (Faithe Wempen, "Computing Fundamentals: Introduction to Computers", 2015)