THE GALLEY PARALLEL FILE SYSTEM

Most current multiprocessor file systems are designed to use multiple disks in parallel, using the high aggregate bandwidth to meet the grow ing I/O requirements of parallel scientific applications, Many multipr ocessor file systems provide applications with a conventional Unix-lik e interface, allowing the application to access multiple disks transpa rently. This interface conceals the parallelism within the file system , increasing the ease of programmability, but making it difficult or i mpossible for sophisticated programmers and libraries to use knowledge about their I/O needs to exploit that parallelism. In addition to pro viding an insufficient interface, most current multiprocessor file sys tems are optimized for a different workload than they are being asked to support. We introduce Galley, a new parallel file system that is in tended to efficiently support realistic scientific multiprocessor work loads. We discuss Galley's file structure and application interface, a s well as the performance advantages offered by that interface.