Abstract: A shared storage distributed file system is presented that provides users and applications with transparent access to shared data stored on network attached storage devices by utilizing layering techniques to inherit file management functionality from existing file systems. The present invention stores meta-data for the shared data as real-data in a standard, non-modified, client-server distributed file system, such as NFS. In effect, the standard client-server file system acts as a meta-data server. The name space consisting of inode files stored as real-data on the meta-data server acts as the name space for the shared data. Similarly, file attributes of the inode files are utilized as the file attributes of the shared data. By utilizing an existing client-server system as the meta-data server, development time and complexity are greatly reduced, while speed advances in the underlying client-server system may be incorporated without alteration of the present invention.

Abstract: A shared storage distributed file system is presented that provides applications with transparent access to a storage area network (SAN) attached storage device. This is accomplished by providing clients read access to the devices over the SAN and by requiring most write activity to be serialized through a network attached storage (NAS) server. Both the clients and the NAS server are connected to the SAN-attached device over the SAN. Direct read access to the SAN attached device is provided through a local file system on the client. Write access is provided through a remote file system on the client that utilizes the NAS server. A supplemental read path is provided through the NAS server for those circumstances where the local file system is unable to provide valid data reads. Consistency is maintained by comparing modification times in the local and remote file systems.