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From: dillon@flea.best.net (Matt Dillon)
Newsgroups: comp.unix.bsd.freebsd.misc,comp.unix.bsd.bsdi.misc,comp.sys.sgi.misc
Subject: Re: no such thing as a "general user community"
Date: 21 Mar 1997 13:08:19 -0800
Organization: BEST Internet Communications, Inc.
Lines: 26
Message-ID: <5gutc3$l4@flea.best.net>
References: <331BB7DD.28EC@net5.net> <5goqrq$5ak$1@news.clinet.fi> <5gpcf9$767@flea.best.net> <3331C5DF.7284@cet.co.jp>
NNTP-Posting-Host: flea.best.net
Xref: euryale.cc.adfa.oz.au comp.unix.bsd.freebsd.misc:37562 comp.unix.bsd.bsdi.misc:6436 comp.sys.sgi.misc:29371
:In article <3331C5DF.7284@cet.co.jp>, H. Asatani <bjc@cet.co.jp> wrote:
:>Matt Dillon wrote:
:>>
:>> XFs's claim to fame is:
:>>
:>> * hashed directory lookups, making namei() on large directories more
:>> efficient (but only on large directories).
:>
:>Are you talking about an on disk structure. FBSD has a simple sequential on disk
:>directory structure. There is a hashed name cache so assuming locality of
:>reference...
Yes, of course I am talking about the on-disk structure. Nobody builds
an O(N) cache for this sort of stuff. The on-disk structure is extremely
important under load, when the namei() cache hit ratio falls below 90%.
:>Is this a log (journaling) system?
:>
:>FBSD has something called LFS but it is completely different. It's a log
:>structured file system written by Margo Seltzer now at Harvard. In a log
:>structured fs the files are the logs themselves. It optimises write performance
:>over reads, heavily assuming LOR. They showed studies where the amount of actual
Good question. I don't know how XFS is classed.
-Matt