Research On Metadata Management Of Parallel File System

With the emergence of high-performance microprocessor, high-speed network and the increscent demand of computing power, cluster of computer with cheap hardware and software is more and more used by users, which brings the quick development of cluster technologies. Cluster file system is an important component of a cluster. As a parallel file system on the cluster architecture, cluster file system provides a unified interface of accessing great capability storage and high I/O bandwidth for the users. Owing to the file data spreading around the cluster, locating a file needs the help of metadata, so managing metadata becomes a key of managing data.In order to improve the reliability of metadata managing, a fault-tolerant metadata management system is wanted. So we design a dual metadata server system for the cluster file system. In this system, there are two metadata servers and the reliability of metadata is provided by metadata mirroring, and the continuous metadata service is provided by failover: after the master server fails, the backup server takes over the metadata service. This system has the merits of the center metadata management: simple control, easy to implement and maintain, but overcomes the shortcoming of single point of failures. At the same time, it avoids the design and cost of keeping consistency of the distributing metadata management. We implement metadata mirroring, failure detecting, IP takeover and recovery in Linux kernel space, which is transparent to the applications. The last aim of this system is to extend its architecture to the multi-host to get greater fault-tolerant ability and come to high availability. In order to improve the efficiency of metadata server, an autoecious metadata storing and managing method is presented. Metadata of parallel file system are located in the kernel of the local file system and operate it by adding system call, which provides the compatibility of original system. When we apply this method on the metadata management of PVFS(Parallel Virtual File System), the test result indicates that the improved performance is about 5~8 times greater than the original method of it.