From owner-freebsd-questions@FreeBSD.ORG Thu Jul 28 19:07:14 2005 Return-Path: X-Original-To: freebsd-questions@freebsd.org Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 5F80D16A424 for ; Thu, 28 Jul 2005 19:07:14 +0000 (GMT) (envelope-from freebsd-questions-local@be-well.ilk.org) Received: from mail24.sea5.speakeasy.net (mail24.sea5.speakeasy.net [69.17.117.26]) by mx1.FreeBSD.org (Postfix) with ESMTP id 09FA643D46 for ; Thu, 28 Jul 2005 19:07:13 +0000 (GMT) (envelope-from freebsd-questions-local@be-well.ilk.org) Received: (qmail 6383 invoked from network); 28 Jul 2005 19:07:13 -0000 Received: from dsl092-078-145.bos1.dsl.speakeasy.net (HELO be-well.ilk.org) ([66.92.78.145]) (envelope-sender ) by mail24.sea5.speakeasy.net (qmail-ldap-1.03) with SMTP for ; 28 Jul 2005 19:07:13 -0000 Received: by be-well.ilk.org (Postfix, from userid 1147) id 91D672F; Thu, 28 Jul 2005 15:07:12 -0400 (EDT) Sender: lowell@be-well.ilk.org To: Bob Johnson References: <200507281157.42688.bob89@eng.ufl.edu> From: Lowell Gilbert Date: 28 Jul 2005 15:07:12 -0400 In-Reply-To: <200507281157.42688.bob89@eng.ufl.edu> Message-ID: <44ll3qu4v3.fsf@be-well.ilk.org> Lines: 41 User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.3 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Victor Semionov , freebsd-questions@freebsd.org Subject: Re: defragmentation in FreeBSD 4.11 X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 28 Jul 2005 19:07:14 -0000 Bob Johnson writes: > Message: 6 > Date: Thu, 28 Jul 2005 11:20:31 +0300 > From: Victor Semionov > Subject: Re: defragmentation in FreeBSD 4.11 > To: freebsd-questions@freebsd.org > Message-ID: <200507281120.31564.victor@vmpbg.com> > Content-Type: text/plain; charset="windows-1251" > > > > > This is one of the things I find really hard to get Windows users to > > > understand. They just won't believe that a company like Microsoft would > > > still be using a filesystem that needs defragmenting if it were possible > > > to design one that didn't. I often wonder why myself - after all, they > > > must have put a fair amount of work into NTFS, which at least doesn't > > > seem to get corrupted in a power failure. Did they make a trade-off I > > > don't understand, or is it just incompetence - or worse, a deal with > > > disk manufacturers to sell more disk? > > > > Microsoft used to claim that NTFS doesn't need defragmentation. Compared to > MSDOSFS, that's a reasonably accurate statement, but if you push it hard > enough, it will still become fragmented. > > > Why is it unnecessary to defragment UFS? > > > > In normal use, files never become fragmented enough to affect performance. In > a (loose) sense, files are intentionally fragmented in a controlled way so > that fragmentation doesn't cause problems. If you run fsck on a partition, > you will typically see fragmentation levels of less than one percent. Careful, there; "fragmentation" on a UFS is measuring a completely different thing than the same term applied to a Microsoft filesystem. For UFS, it refers to non-contiguous free blocks (fragments, actually), as opposed to the Microsoft terminology, where it refers to non-contiguous blocks within the same file. Everything you are saying is correct, but it will confuse people who don't realize the difference.