WorkOut: I/O Workload Outsourcing for Boosting RAID Reconstruction Performance

As a fundamental technology for reliability and availability, RAID has been widely deployed in modern storage systems. A RAID-structured storage system ensures that data will not be lost when disks fail. One of the key responsibilities of RAID is to recover the data that was on a failed disk, a process known as RAID reconstruction. The performance of RAID reconstruction techniques depends on two factors. The time it takes to complete the reconstruction of a failed disk, since longer reconstruction times translate to a longer \"Window of vulnerability\", in which a second disk failure may cause persistent data loss. The impact of the reconstruction process on the foreground workload, i.e., to what degree is user requests affected by the ongoing reconstruction.