redundancy

1. Additional information stored along with user data that enables a RAID controller module to reconstruct lost data. Redundant Array of Independent Disks (RAID) 1 uses mirroring for redundancy. RAID 5 and RAID 6 use redundancy information, sometimes called parity, that is constructed from the data bytes and is striped along with the data on each physical disk. 2. The use of enclosures that are not necessary for normal system operation. The enclosures are substituted for another component or can perform the same function as another component. This use allows the system to remain operational if the component fails.