*BSD News Article 65274


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From: kls@MAILBOX.SLAC.Stanford.EDU (Karl L. Swartz)
Newsgroups: comp.unix.bsd.freebsd.misc,news.admin.technical,news.software.nntp
Subject: Re: Poor performance with INN and FreeBSD.
Date: 9 Apr 1996 11:49:22 -0400
Organization: Stanford Linear Accelerator Center
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In article <4itdar$oqh@sunrise.gv.ssi1.com>,
Don Lewis <gdonl@gv.ssi1.com> wrote:

>I believe the "toaster" has a non-volatile write cache for it's disks,
>which would speed up file creation and deletion significantly, since
>these usually involve synchronous writes to the disk on your typical
>Unix local filesystem.

Yes, it does, and that's certainly part of the performance boost.  The
other big part is that an in-core hash table for each directory is
built when the directory is accessed, so adding a file to a directory
with n files in it is O(1) instead of O(n).

>I've heard that Suns with Prestoserve boards (which are generally
>installed to optimize NFS serving) experience a similar performance
>boost.  Expire is reported to run really fast ;-)

I hadn't thought of that before but it certainly makes sense.  You can
help expire with INN's fastpurge (?) feature, though, while creating a
file still requires a linear search of the whole directory to make
sure there isn't already a file with the desired name.  The toaster's
hash table addresses that problem nicely.

-- 
Karl Swartz		|INet	kls@unixhub.slac.stanford.edu
SLAC Computing Services	|	   or kls@chicago.com
1-415/926-3630		|UUCP	uunet!lll-winken!unixhub!kls  -or-  ditka!kls
(SLAC and the US Dept. of Energy don't necessarily agree with my opinions.)