Log-structured file system: Difference between revisions

Revision as of 00:12, 1 May 2008

Revision as of 03:49, 30 May 2008

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== Disadvantages ==

* The design rationale for log-structured file systems assumes that most reads will be optimized away by ever-enlarging memory caches. This assumption isdoes not truealways for all workloadshold:
** onOn magnetic media (wheremedia—where seeks are relatively expensive) theexpensive—the log structure may actually make reads much slower, since it [[fragmentation (computer)#External_fragmentation|fragments]] files that conventional file systems normally keep contiguous with in-place writes. Mechanical seek limitations do not apply to flash memory.

** On flash memory—where seek times are usually negligible—the log structure may not confer a worthwhile performance gain because write fragmentation has much less of an impact on write throughput.

== References ==