An OSD-based approach to managing directory operations in parallel file systems

Abstract

Distributed file systems that use multiple servers to store data in parallel are becoming commonplace. Much work has already gone into such systems to maximize data throughput. However, metadata management has historically been treated as an afterthought. In previous work we focused on improving metadata management techniques by placing file metadata along with data on object-based storage devices (OSDs). However, we did not investigate directory operations. This work looks at the possibility of designing directory structures directly on OSDs, without the need for intervening servers. In particular, the need for atomicity is a fundamental requirement that we explore in depth. Through performance results of benchmarks and applications we show the feasibility of using OSDs directly for metadata, including directory operations.