[Sussex] Why Linux doesn't need defrag

[Geoff Teale]

To be honst I'm not convinced *any* file system needs defragging on a regular basis.

Whilst different filesystems storage structures will have an effect I reckon the following factors are important:

 - the size of disks generally (the more free space you have, the less time is spent looking for space to) - in fact ackowledging that disk space is cheap  could be a driver to writing an I/O system that sacrifices capactiy for a greater number of continguous blocks on disk.
 - I/O scheduling in the Linux kernel is pretty darn clever
 - the speed of disks is so great now that the slow downs that fragmentation may cause aren't noticed by j.random user.

.. I think the fact we're even discussing fragmentation in persitant memory is testament to the fact that many of us once used a crap OS on machines with very full 100MB hard disks.  :-)

-- 
Geoff Teale
Software Engineering Team Manager

Cmed Group Ltd.
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