Directory Structure of a New SAN-Based Shared File System

摘要

Based on the storage area network(SAN), LINUX cluster file systems have been developed recently. The Global File System(GFS) developed at the University of Minnesota is such an example. These systems do not have a central file server, however instead multiple clients sharing the whole disk storage through Fibre Channel can freely access disk storage and act as file servers. Therefore, they can offer advantages such as availability, load balancing, and scalability. In this paper, we describe the directory structure of SANtopia. which is now being developed at ETRI as a new shared disk cluster file system for LINUX in the SAN environment. First, we present a new inode structure called semiflat structure that is more efficient than previous inode structures in disk block access time. Second, we describe a new directory structure using the semiflat inode structure. Additionally, we present a novel scheme to manage disk free space which is suitable for very large file svstems. Through performance evaluation, we show that the proposed schemes have better peiformance than previous ones.