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Re: Quota definitions

On Tue, Jul 28, 2009 at 01:23:39PM +0200, Manuel Bouyer wrote:
 > I would go with a new format. The current format is a table indexed
 > by uid or gid. If you use large uid you get a very large sparse file.
 > A different indexing scheme is needed.

I'm not convinced. Linux did this and I don't really see the point -
instead of reusing the FS's tree structure for managing a sparse file,
they added another layer of tree structure, which buys complexity and
recovery problems and not a whole lot else.

Because uids mostly tend to come in contiguous sequences, I'm not
convinced that in practice one will tend to see quota files with lots
of blocks that each hold the info for one user and are otherwise
empty. Except maybe on large installations with lots of uids and lots
of uid turnover, but even then I expect a much bigger problem is that
quota records for removed users probably aren't ever G/C'd.

Anyone have data to prove me wrong? :-)

(more on the rest later)

David A. Holland

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