From owner-freebsd-questions Sun Mar 3 6: 7:28 2002 Delivered-To: freebsd-questions@freebsd.org Received: from gromit.dlib.vt.edu (gromit.dlib.vt.edu [128.173.49.29]) by hub.freebsd.org (Postfix) with ESMTP id 6BE1737B416 for ; Sun, 3 Mar 2002 06:07:24 -0800 (PST) Received: from mule.Chelsea-Ct.Org (h80ad279d.async.vt.edu [128.173.39.157]) by gromit.dlib.vt.edu (8.10.1/8.10.1) with ESMTP id g23E7K524745; Sun, 3 Mar 2002 09:07:20 -0500 (EST) Date: Sun, 3 Mar 2002 09:07:14 -0500 (EST) From: Paul Mather X-X-Sender: paul@mule.Chelsea-Ct.Org To: C J Michaels Cc: questions@freebsd.org Subject: RE: defragment UFS In-Reply-To: Message-ID: <20020303085739.J83257-100000@mule.Chelsea-Ct.Org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On Sun, 3 Mar 2002, C J Michaels wrote: => > From: Paul Mather => > Sent: Saturday, March 02, 2002 8:00 PM => > Subject: Re: defragment UFS [...] => > It's not really fiction. The smallest unit of disk space the end part => > of a file can occupy in a FFS filesystem is a fragment. Usually this is => > 1/8th the block size, and in 4.5, the default block size is 16 KB and => > default fragment size 2 KB. So, for example, the date of a 16385 byte => > file in such a file system would actually take up an extra 2047 bytes => > "on disk" compared to the reported file size. => => I didn't mean to imply the concept of slack space/fragmentation was fiction. => What I'm saying is that the numbers being reported by windows was fiction. => I'm not sure whether Windows or Samba is at fault, but the "size on disk" => calculations are way off the mark. I guess I should have clarified that. I'm sorry, I did misunderstand what you were saying. Thanks for clarifying. => > Anyway, that is why the "size on disk" will *always* be >= the "size" => > for any given file. Aside from some confusing typos above (it should be the "data," not "date" of a 16385 byte file:), I did make one important incorrect statement, I realise. Files with holes *can* violate the above axiom. (But, for "normal" files, it holds true.) :-) Cheers, Paul. e-mail: paul@gromit.dlib.vt.edu "Without music to decorate it, time is just a bunch of boring production deadlines or dates by which bills must be paid." --- Frank Vincent Zappa To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message