Log-structured file systems

A discussion is presented of several techniques for improving I/O performance, including caches, battery-backed-up caches, and cache logging. The authors then examine in particular detail an approach called log-structured file systems, where the file system's only representation on disk is in the form of an append-only log. Log-structured file systems potentially provide order-of-magnitude improvements in write performance. When log-structured file systems are combined with arrays of small disks (which provide high bandwidth) and large main-memory file caches (which satisfy most read accesses), the authors believe it will be possible to achieve 1000-fold improvements in I/O performance over current systems.<<ETX>>