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Date: Tue, 18 Jan 2005 01:32:10 +0100
From: Erik Trulsson <ertr1013@student.uu.se>
To: Kris Kennaway <kris@obsecurity.org>
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Subject: Re: Slow directory access with lots of files
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On Mon, Jan 17, 2005 at 02:49:11PM -0800, Kris Kennaway wrote:
> On Mon, Jan 17, 2005 at 09:34:25PM +0100, Miguel Mendez wrote:
> > On Mon, 17 Jan 2005 11:13:43 -0800
> > Kris Kennaway <kris@obsecurity.org> wrote:
> > 
> > Hi,
> > 
> > > Do you have UFS_DIRHASH in your kernel?  If you don't, or if you added
> > > it after the disk was already populated, you'll see the benefits if
> > > you dump, wipe and restore the disk.
> > 
> > Could you elaborate on that? My impression has always been that dirhash
> > does all its magic in memory, without persistant data stored on disk.
> 
> No.  It's an optimized method for laying out the data on disk.  I
> think you're confusing it with softupdates, but that still doesn't
> work entirely that way.

No, this time it is you who are confused.  UFS_DIRHASH does not affect
the layout on disk at all as far as I can tell.
You are probably confusing it with the dirpref changes that were made
back in 2001 at approximately the same time as UFS_DIRHASH was added.


-- 
<Insert your favourite quote here.>
Erik Trulsson
ertr1013@student.uu.se