Seek-Efficient I/O Optimization in Single Failure Recovery for XOR-Coded Storage Systems

Abstract

Erasure coding provides an effective means for storage systems to protect against disk failures with low redundancy. One important objective for erasure-coded storage systems is to speed up single disk failure recovery. Previous approaches reduce the amount of read data for recovery by reading only a small subset of data. However, they often incur high disk seeks, which may negate the resulting recovery performance. We propose <i>SIOR</i> , a seek-efficient I/O recovery algorithm for improving the performance of single disk failure recovery. SIOR carefully balances the trade-off between the amount of read data and the number of disk seeks by considering the data layout at the multi-stripe level. It then greedily determines the data to read for recovery using Tabu search. Experiments show that SIOR achieves similar performance to the brute-force enumeration method while keeping high search efficiency. Also, SIOR reduces <inline-formula><tex-math notation="LaTeX">$31.8\sim 65.1$</tex-math></inline-formula> percent of disk seeks during recovery and provides up to 150.0 percent recovery speed improvement, when compared to a state-of-the-art greedy recovery approach.