PHR: A Pipelined Heterogeneous Recovery for RAID6-Coded Storage Systems

With the rapid growth of data and the growing demand from users on the system performance, data availability has become the most important issue in large-scale storage systems. Due to the ability to provide space-optimal data redundancy to protect against node failures, erasure codes have seen widely deployment. To ensure data availability, it is crucial to recover node failures quickly. In this paper, we propose PHR, a pipelined heterogeneous recovery optimization for failure recovery in RAID-6 coded storage systems. Our PHR takes into account both I/O parallelism and node heterogeneity in practical storage systems, and returns an efficient recovery solution timely. We parallelize our PHR algorithm in a pipelined manner, so as to further improve failure recovery performance. With the quantitative simulation studies and extensive test bed experiments, we show our PHR significantly reduces recovery time and also user response time.