Avoiding file system micromanagement with range writes
Ashok Anand, Sayandeep Sen, Andrew Krioukov, Florentina I. Popovici, Aditya Akella, Andrea Carol Arpaci-Dusseau, Remzi H. Arpaci-Dusseau, Suman Banerjee · 2008
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.