The design and implementation of a distributed file system based on shared network storage

Distributed file systems allow users to access and share files from any computer connected to the distributed system. Distributed file systems typically do not achieve the same level of performance that local file systems provide due to the demands of resource sharing. For workloads with large storage capacity requirements, poor performance of distributed file systems often overshadows the benefits of transparent file sharing. Traditional network and channel interfaces differ in performance, connectivity, and connection distance. By merging network and channel interfaces, resulting interfaces allow multiple computers to physically share storage devices. Computers service local file requests directly from network attached storage devices. Direct device access eliminates server machines as bottlenecks to performance and availability. Communication is unnecessary between computers, since each machine views storage as locally attached. This dissertation presents a distributed file system design based on a shared network storage architecture. The architecture distributes user workloads and file system resources across the entire system. Functions once performed by server computers are redistributed to clients and storage devices. The design brings responsibilities, such as caching and consistency management, closer to hardware, so that these functions execute faster and more reliably. The Global File System (GFS) is a distributed file system prototype built upon Fibre Channel networks. GFS is implemented in the Silicon Graphics IRIX operating system and is accessed using standard UNIX commands and utilities. GFS uses a consistency mechanism that is prototyped on Seagate disk drives and Ciprico disk arrays. This dissertation describes the architecture and implementation of the file system design. Performance analysis is given for the file system prototype in large data demand environments.