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Avoiding File System Micromanagement with Range Writes

Ashok Anand, Sayandeep Sen, Andrew Krioukov, Florentina Popovici,

Aditya Akella, Andrea Arpaci-Dusseau, Remzi Arpaci-Dusseau, Suman Banerjee

University of Wisconsin, Madison

Abstract:

We introduce range writes, a simple but powerful change to the disk interface that removes the need for file system micromanagement of block placement. By allowing a file system to specify a set of possible address targets, range writes enable the disk to choose the final on-disk location of the request; the disk improves performance by writing to the closest location and subsequently reporting its choice to the file system above. The result is a clean separation of responsibility; the file system (as high-level manager) provides coarse-grained control over placement, while the disk (as low-level worker) makes the final fine-grained placement decision to improve write performance. We show the benefits of range writes through numerous simulations and a prototype implementation, in some cases improving performance by a factor of three across both synthetic and real workloads.