Storing the same data in more than one file. 13.11, 13.13

In computer storage, data redundancy (sometimes incorrectly referred to as data reliability) is a property of some disk arrays which provides fault tolerance such that if some disks fail, all or part of the data stored by the array is not lost. The cost of providing this feature is most typically increased disk space; implementations require either a duplication of the entire data set or an error-correcting code to be stored on the array.