Characteristics of a Production Parallel Scienti c Workload

Multiprocessors have permitted astounding increases in computational performance but many cannot meet the intense I O requirements of some scienti c applications An important component of any solution to this I O bottleneck is a parallel le system that can provide high bandwidth access to tremendous amounts of data in parallel to hundreds or thousands of processors Most successful systems are based on a solid understanding of the expected workload but thus far there have been no comprehensive workload characterizations of multiprocessor le systems This paper presents the results of a three week tracing study in which all le related activity on a massively parallel computer was recorded Our instrumentation di ers from pre vious e orts in that it collects information about every I O request and about the mix of jobs running in a production environment We also present the results of a trace driven caching simulation and recommendations for designers of multiprocessor le systems