From owner-freebsd-fs@FreeBSD.ORG  Sat Mar 26 22:08:12 2005
Return-Path: <owner-freebsd-fs@FreeBSD.ORG>
Delivered-To: freebsd-fs@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP
	id F35AC16A4CE; Sat, 26 Mar 2005 22:08:11 +0000 (GMT)
Received: from critter.freebsd.dk (f170.freebsd.dk [212.242.86.170])
	by mx1.FreeBSD.org (Postfix) with ESMTP
	id DC09D43D41; Sat, 26 Mar 2005 22:08:10 +0000 (GMT)
	(envelope-from phk@critter.freebsd.dk)
Received: from critter.freebsd.dk (localhost [127.0.0.1])
	by critter.freebsd.dk (8.13.3/8.13.1) with ESMTP id j2QM86k9017694;
	Sat, 26 Mar 2005 23:08:06 +0100 (CET)
	(envelope-from phk@critter.freebsd.dk)
To: David Schultz <das@freebsd.org>
From: "Poul-Henning Kamp" <phk@phk.freebsd.dk>
In-Reply-To: Your message of "Sat, 26 Mar 2005 16:30:48 EST."
             <20050326213048.GA33703@VARK.MIT.EDU> 
Date: Sat, 26 Mar 2005 23:08:06 +0100
Message-ID: <17693.1111874886@critter.freebsd.dk>
Sender: phk@critter.freebsd.dk
cc: David Malone <dwmalone@maths.tcd.ie>
cc: freebsd-fs@freebsd.org
Subject: Re: UFS Subdirectory limit. 
X-BeenThere: freebsd-fs@freebsd.org
X-Mailman-Version: 2.1.1
Precedence: list
List-Id: Filesystems <freebsd-fs.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-fs>,
	<mailto:freebsd-fs-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-fs>
List-Post: <mailto:freebsd-fs@freebsd.org>
List-Help: <mailto:freebsd-fs-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-fs>,
	<mailto:freebsd-fs-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sat, 26 Mar 2005 22:08:12 -0000

In message <20050326213048.GA33703@VARK.MIT.EDU>, David Schultz writes:
>On Fri, Mar 25, 2005, Scott Long wrote:
>> David Schultz wrote:
>> >On Sat, Mar 26, 2005, David Malone wrote:
>> >
>> >>There was a discussion on comp.unix.bsd.freebsd.misc about two weeks
>> >>ago, where someone had an application that used about 150K
>> >>subdirectories of a single directory. They wanted to move this
>> >>application to FreeBSD, but discovered that UFS is limited to 32K
>> >>subdirectories, because UFS's link count field is a signed 16 bit
>> >>quantity. Rewriting the application wasn't an option for them.

Has anybody here wondered how much searching a 150K directory would
suck performance wise ?

I realize that with dir-hashing and vfs-cache it is not as bad as it
used to be, but I still think it will be unpleasant performance wise.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.