Problems with FFS and directories of over 1000 entries....

[Matthew Seaman]

On Thu, Mar 04, 2004 at 02:42:54PM -0500, Forrest Aldrich wrote:
> I understand that FFS has some performance problems in directory/file 
> structures that have over 1000 entires... though I'm not sure this 
> applies to FFS under FreeBSD-5.x.   Can someone comment on this?

No -- you understand incorrectly.  Large directories have not been a
problem since UFS_DIRHASH went into the tree, which was, oh, two and a
half years ago:

    http://docs.freebsd.org/cgi/getmsg.cgi?fetch=18975+0+archive/2001/freebsd-fs/20010624.freebsd-fs

Not that UFS did badly before that: 1000 entries in one directory
probably wouldn't have been problematic.  10,000 could have been a
different matter.  100,000 would have been difficult to deal with.

UFS_DIRHASH is enabled in the GENERIC kernel, and has been since 2001:

    http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/i386/conf/GENERIC.diff?r1=1.246.2.36&r2=1.246.2.37&only_with_tag=RELENG_4

	Cheers,

	Matthew

-- 
Dr Matthew J Seaman MA, D.Phil.                       26 The Paddocks
                                                      Savill Way
PGP: http://www.infracaninophile.co.uk/pgpkey         Marlow
Tel: +44 1628 476614                                  Bucks., SL7 1TH UK
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