File-system workload on a scientific multiprocessor

The Charisma project records individual read and write requests in live, multiprogramming parallel workloads. This information can be used to design more efficient multiprocessor systems. We present the first results from the project: a characterization of the tile-system workload on an iPSC/860 multiprocessor running production, parallel scientific applications at NASA Ames Research Center. We use the resulting information to address the following questions: What did the job mix look like (that is, how many jobs ran concurrently?) How many files were read and written? Which were temporary files? What were their sizes? What were typical read and write request sizes, and how were they spaced in the file? Were the accesses sequential? What forms of locality were there? How might caching be useful? What are the implications for file-system design?