基于EVENODD码的单盘故障快速恢复算法

摘要

In EVENODD code storage systems, fast recovery for single disk failure is a hot issue. By reducing the amount of data needed to be read out during recovery, the recovery process is speeded up and the data storage reliability is enhanced. This paper theoretically confirms the lower bound of the amount of data read from other disks for any single disk failure recovery, and proposes a new hybrid recovery algorithm which achieves the amount of data read as closer to the lower bound as possible. Compared with the conventional recovery algorithm that carries out only one parity check, the hybrid recovery algorithm carries out both parity checks in EVENODD code to recover the single failed disk in order to significantly reduce disk read operations. Experiment results show that the hybrid recovery algorithm outperforms the conventional algorithm in terms of both total recovery time and disk access frequency.%在基于EVENODD码的阵列存储系统中,考虑单个磁盘故障时的快速恢复问题,通过减少恢复过程中数据的读取量来减少恢复时间,提高数据存储的可靠性.理论上证明了对于任意单个磁盘的故障恢复,需要从系统中其他盘读取的数据量的下界,井设计出一种新的混合恢复算法,使得恢复过程中的数据读取量达到该理论下界.相比于传统恢复算法,混合恢复算法综合利用了EVENODD码的两类校验进行单盘恢复,能够有效地减少恢复时所需的数据读取量.实验结果表明混合恢复算法在恢复时间和磁盘访问时间方面相比于传统算法有明显的提高.