UC Santa Cruz

Disk scrubbing periodically scans the contents of a disk array to detect the presence of irrecoverable read errors and reconstitute the contents of the lost blocks using the builtin redundancy of the disk array. We address the issue of scheduling scrubbing runs in disk arrays that can tolerate two disk failures without incurring a data loss, and propose to start an urgent scrubbing run of the whole array whenever a disk failure is detected. Used alone or in combination with periodic scrubbing runs, these expedited runs can improve the mean time to data loss of disk arrays over a wide range of disk repair times. As a result, our technique eliminates the need for frequent scrubbing runs and the need to maintain spare disks and personnel on site to replace failed disks within a twenty-four hour interval. © 2010 IEEE.