The Global File System

The Global File System (GFS) is a prototype design for a distributed file system in which cluster nodes physically share storage devices connected via a network like Fibre Channel. Networks and network attached storage devices have advanced to a level of performance and extensibility that the once believed disadvantages of “shared disk” architectures are no longer valid. This shared storage architecture attempts to exploit the sophistication of device technologies where as the client–server architecture diminishes a device’s role to a simple components. GFS distributes the file system responsibilities across the processing nodes, storage across the devices, and file system resources across the entire storage pool. GFS caches data on the storage devices instead of the main memories of the machines. Consistency is established by using a locking mechanism maintained by the storage device controllers to facilitate atomic read–modify– write operations. The locking mechanism is being prototyped on Seagate disks drives and Ciprico disk arrays. GFS is implemented in the Silicon Graphics IRIX operating system and is accessed using standard Unix commands and utilities. This work was supported by the Office of Naval Research under grant no. N00019-95-1-0611, by the National Science Foundation under grant no. ASC-9523480, and by grant no. 5555-23 from the University Space Research Association which is administered by NASA’s Center for Excellence in Space Data and Information Sciences (CESDIS) at the NASA Goddard Space Flight Center.