IDO: Intelligent Data Outsourcing with Improved RAID Reconstruction Performance in Large-Scale Data Centers
Dealing with disk failures has become an increasingly common task for system administrators in the face of high disk failure rates in large-scale data centers consisting of hundreds of thousands of disks. Thus, achieving fast recovery from disk failures in general and high online RAID-reconstruction performance in particular has become crucial. To address the problem, this paper proposes IDO (Intelligent Data Outsourcing), a proactive and zone-based optimization, to significantly improve on-line RAID-reconstruction performance. IDO moves popular data zones that are proactively identified in the normal state to a surrogate set at the onset of reconstruction. Thus, IDO enables most, if not all, user I/O requests to be serviced by the surrogate set instead of the degraded set during reconstruction.