A multiple-file write scheme for improving write performance of small files in Fast File System

Abstract

Fast File System (FFS) stores files to disk in separate disk writes, each of which incurs a disk positioning (seek + rotation) limiting the write performance for small files. We propose a new scheme called co-writing to accelerate small file writes in FFS without sacrificing its advantages. The scheme collects writes to small files in the same directory and stores them together to disk in a single large disk write. Co-writing multiple files in one disk I/O can reduce disk positioning times resulting from small file writes in FFS. Our experiments on OpenBSD show that the co-writing slashes the cost of small file writes in FFS by up to 33%, in both real-world and synthetic benchmarks.