From owner-freebsd-fs@FreeBSD.ORG Wed Nov 19 23:15:23 2008 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 5E74D1065672 for ; Wed, 19 Nov 2008 23:15:23 +0000 (UTC) (envelope-from dan-freebsd-fs@ourbrains.org) Received: from ourbrains.org (li48-221.members.linode.com [66.246.76.221]) by mx1.freebsd.org (Postfix) with SMTP id EE4C98FC13 for ; Wed, 19 Nov 2008 23:15:22 +0000 (UTC) (envelope-from dan-freebsd-fs@ourbrains.org) Received: (qmail 7667 invoked by uid 1000); 19 Nov 2008 23:15:43 -0000 Date: Wed, 19 Nov 2008 18:15:43 -0500 From: Dan To: freebsd-fs@freebsd.org Message-ID: <20081119231543.GA7659@ourbrains.org> Mail-Followup-To: freebsd-fs@freebsd.org References: <20081119052428.GC4136@ourbrains.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.18 (2008-05-17) Subject: Re: (no subject) X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 19 Nov 2008 23:15:23 -0000 Nick Barkas(nick.barkas@gmail.com)@2008.11.19 14:29:24 +0100: > I'm not sure if this is what you're looking for, but FreeBSD's does > have some provisions to avoid too much performance degradation with > large directories. The VFS name cache will speed up look-up operations > on specific individual files in any size directory that are repeatedly > searched for, and it is filesystem independent. Specific to UFS2 there > is dirhash, which was implemented by Ian Dowse and David Malone. It > speeds up more types of operations involving large directories. They I know. dirhash on only great until a few dozen thousand files, then it blows out. You might be interested in the dicussion here: http://leaf.dragonflybsd.org/mailarchive/kernel/2008-11/msg00055.html