PRO: A Popularity-based Multi-threaded Reconstruction Optimization for RAID-Structured Storage Systems

This paper proposes and evaluates a novel dynamic data reconstruction optimization algorithm, called popularity-based multi-threaded reconstruction optimization (PRO), which allows the reconstruction process in a RAID-structured storage system to rebuild the frequently accessed areas prior to rebuilding infrequently accessed areas to exploit access locality. This approach has the salient advantage of simultaneously decreasing reconstruction time and alleviating user and system performance degradation. It can also be easily adopted in various conventional reconstruction approaches. In particular, we optimize the disk-oriented reconstruction (DOR) approach with PRO. The PRO-powered DOR is shown to induce a much earlier onset of response-time improvement and sustain a longer time span of such improvement than the original DOR. Our benchmark studies on read-only web workloads have shown that the PRO-powered DOR algorithm consistently outperforms the original DOR algorithm in the failurerecovery process in terms of user response time, with a 3.6%-23.9% performance improvement and up to 44.7% reconstruction time improvement simultaneously.