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USENIX, The Advanced Computing Systems Association

OSDI '06 Abstract

Pp. 114 of the Proceedings

Awarded Best Paper!

Rethink the Sync

Edmund B. Nightingale, Kaushik Veeraraghavan, Peter M. Chen, and Jason Flinn, University of Michigan


We introduce external synchrony, a new model for local file I/O that provides the reliability and simplicity of synchronous I/O, yet also closely approximates the performance of asynchronous I/O. An external observer cannot distinguish the output of a computer with an externally synchronous file system from the output of a computer with a synchronous file system. No application modification is required to use an externally synchronous file system: in fact, application developers can program to the simpler synchronous I/O abstraction and still receive excellent performance. We have implemented an externally synchronous file system for Linux, called xsyncfs. Xsyncfs provides the same durability and ordering guarantees as those provided by a synchronously mounted ext3 file system. Yet, even for I/O-intensive benchmarks, xsyncfs performance is within 7% of ext3 mounted asynchronously. Compared to ext3 mounted synchronously, xsyncfs is up to two orders of magnitude faster.
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Last changed: 23 April 2007 ac