Slow directory access with lots of files
kris at obsecurity.org
Mon Jan 17 21:10:07 PST 2005
On Tue, Jan 18, 2005 at 01:32:10AM +0100, Erik Trulsson wrote:
> 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 at 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.
Sorry, you're right!
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