Efficient techniques of parallel recovery for erasure-coding-based distributed file systems

Replication has been widely used to ensure the data availability in a distributed file system. In recent years, erasure coding (EC) has been adopted to overcome the problem of space efficiency in Replication. However, EC has various performance degrading factors such as parity calculation and degraded input/output. In particular, the recovery performance of EC is degraded because of various factors when the distributed file systems become large. Nonetheless, few studies have been conducted to improve the recovery performance. Thus, this paper proposes an efficient parallel recovery technique in an EC-based distributed file system. We describe the contention avoidance method, chunk allocation method, and asynchronous recovery method, to improve the parallel recovery performance. The contention avoidance method can minimize the contention for resources. The chunk allocation method and asynchronous recovery method can increase the efficiency of the parallel recovery. Finally, we verify that when the proposed parallel recovery technique in this paper is applied to actual distributed file systems, its recovery performance is improved by 263% compared to that of existing methods in the performance evaluation.