Ergastulum: quickly finding near-optimal storage system designs

The cost of large storage systems is dominated by management costs. Typically, skilled administrators configure storage manually using rules of thumb. However, designing a storage system for a given workload is a difficult task, because there are millions of possible configurations and mappings of data, and because storage system behavior is complex. Ergastulum is a new storage system designer that can be used both to guide administrators in their design decisions and as part of an automatic storage system management tool like Hippodrome [4]. Ergastulum generalizes the best-fit bin packing heuristic with randomization and backtracking to efficiently search through the huge number of possible design choices. Design decisions are informed by device models that estimate storage system performance. We show that Ergastulum quickly generates near-optimal storage system designs. It is faster and generates better solutions than previous tools, and it is substantially faster than an integer programming implementation that generates optimal solutions for simplified device models. We conclude that Ergastulum is a comprehensive solution to the storage system design problem.