Patent ID: 8417989

Claim:
A method for an extra redundancy in a RAID system, comprising: creating one or more RAID arrays, wherein each RAID array comprises a plurality of disk drives; creating a respective dedicated hot spare for each RAID array; and copying data from each RAID array to the respective dedicated hot spare using a copyback process based on a predetermined controller usage threshold value, wherein the copyback process comprises copying data from one of the plurality of disk drives which has a predictive failure in each RAID array on strip-by-strip basis to the respective dedicated hot spare, wherein the predetermined controller usage threshold value is based on a number of I/O requests initiated by an operating system on a RAID controller, and wherein the copyback process comprises: substantially simultaneously writing data on a strip-by-strip basis to each RAID array and the respective dedicated hot spare upon receiving a write request when the number of I/O requests is less than or equal to the predetermined controller usage threshold value.