Log-structured file system: Difference between revisions

Revision as of 04:55, 28 October 2006

Revision as of 05:03, 28 October 2006

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:''This is about the concept of a log-structured file system. For the NetBSD file system, see [[Log-structured File System]].''

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A '''log-structured filesystem''' is a [[file system]] design first proposed by [[John K. Ousterhout]] and [[Fred Douglis]]. It writes data to the file system in a sequential "log" format, as opposed to the normal scattered blocks format.

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* [[John K. Ousterhout]] and [[Mendel Rosenblum]] implemented the first log-structured file system for the [[Sprite operating system]] in 1992.<ref name=rosenblum92 />

* [[Log-structured File System|BSD-LFS]], an implementation by [[Margo Seltzer]] was added to 4.4BSD, and was later ported to [[386BSD]]. It lacks support for snapshots. It was removed from FreeBSD and OpenBSD, but still lives on in [[NetBSD]].

* [[Plan 9 from Bell Labs|Plan 9]]'s [[Fossil (file system)|Fossil]] file system is also log-structured and supports snapshotting.

* [[NILFS]] is a log-structured file system implementation for [[Linux]] by [[NTT/Verio]] which supports snapshots. It is still in [[development stage]] and not ready for production use.

* [[LogFS]] and [[LinLogFS]] are names used for various Linux log-structured file system implementations, the latest one written for [[Google Summer of Code 2005]], however all of these projects were cancelled.

* [[Reiser4]] calls the concept "[[wandering log]]". It has no support snapshotting.

* [[ZFS]] from [[Sun Microsystems|Sun]] is a log-structured file system which supports snapshotting. However, it uses [[reference-counting]] instead of [[garbage collection (computer science)|garbage collection]] to manage free space.

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[[Category:Linux]]

[[Category:Sun Microsystems]]

[[Category:Bell Labs]]