Log-structured file system: Difference between revisions

Revision as of 11:28, 15 June 2009

Revision as of 18:29, 15 June 2009

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{{this2Otheruses4|the general concept of log-structured file systems|the NetBSD file system|Log-structured File System (BSD)|the Linux log-structured Flash file system|LogFS}}

A '''log-structured filesystem''' is a [[file system]] design first proposed in 1988 by [[John K. Ousterhout]] and [[Fred Douglis]]. Designed for high write throughput, all updates to data and metadata are written sequentially to a continuous stream, called a log. The design was first implemented by Ousterhout and [[Mendel Rosenblum]].

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* [[UBIFS]] for [[Linux]], also intended to replace [[JFFS2]] (in development).

* [[ULFS]] is a User-Level Log-structured File System (http://ulfs.sf.net) Using FUSE (http://fuse.sf.net).

* [[ZFS]] is a log-structured file system available on Solaris, Mac OS X, and FreeBSD.{{cnFact|date=June 2009}}{{Dubious|date=June 2009}}

Some kinds of storage media, such as [[flash memory]] and [[CD-RW]], slowly degrade as they are written to and have a limited number of erase/write cycles at any one ___location. Log-structured file systems are sometimes used on these media because they make fewer in-place writes and thus prolong the life of the device by [[wear levelling]]. The more common such file systems include: