1. <architecture, parallel> The provision of multiple interchangeable components to perform a single function in order to provide resilience (to cope with failures and errors). Redundancy normally applies primarily to hardware. For example, a cluster may contain two or three computers doing the same job. They could all be active all the time thus giving extra performance through parallel processing and load balancing; one could be active and the others simply monitoring its activity so as to be ready to take over if it failed ("warm standby"); the "spares" could be kept turned off and only switched on when needed ("cold standby"). Another common form of hardware redundancy is disk mirroring.
2. <data, communications, storage> data redundancy.
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Nearby terms: Reduced Instruction Set Computer « reduction « reduction strategy « redundancy » Redundant Array of Independent Disks » Redundant Array of Independent Drives » Redundant Array of Inexpensive Disks