Abstract: A storage controller (160) and method (200) for error detection in disk arrays (150) with multiple redundancy by: receiving from each of the disks in the array a linear XOR value derived from data in a desired segment of the unit; comparing the received values from the different disks; and determining, responsive to the comparison, an error in data from one of the disks. Scrubbing is completed by reconstructing, responsive to the error determination, the erroneous data and re-writing it to the erroneous segment. This allows detection of data errors where prior art could not, and detects these errors without a significant increase in controller-disk link data traffic.