From owner-freebsd-current@FreeBSD.ORG Sun Nov 20 12:59:30 2005 Return-Path: X-Original-To: freebsd-current@freebsd.org Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 6B49916A41F for ; Sun, 20 Nov 2005 12:59:30 +0000 (GMT) (envelope-from Alexander@Leidinger.net) Received: from www.ebusiness-leidinger.de (jojo.ms-net.de [84.16.236.246]) by mx1.FreeBSD.org (Postfix) with ESMTP id 9F20543D45 for ; Sun, 20 Nov 2005 12:59:29 +0000 (GMT) (envelope-from Alexander@Leidinger.net) Received: from Andro-Beta.Leidinger.net (p54A5DCEA.dip.t-dialin.net [84.165.220.234]) (authenticated bits=0) by www.ebusiness-leidinger.de (8.13.1/8.13.1) with ESMTP id jAKCYiOD001917; Sun, 20 Nov 2005 13:34:46 +0100 (CET) (envelope-from Alexander@Leidinger.net) Received: from Magellan.Leidinger.net (Magellan.Leidinger.net [192.168.1.1]) by Andro-Beta.Leidinger.net (8.13.3/8.13.3) with ESMTP id jAKCxFbc034250; Sun, 20 Nov 2005 13:59:15 +0100 (CET) (envelope-from Alexander@Leidinger.net) Date: Sun, 20 Nov 2005 13:59:14 +0100 From: Alexander Leidinger To: Peter Jeremy Message-ID: <20051120135914.5ac63e2d@Magellan.Leidinger.net> In-Reply-To: <20051119050216.GU39882@cirb503493.alcatel.com.au> References: <20051118114308.GA11281@uk.tiscali.com> <437DCB6D.6090400@centtech.com> <20051118125922.GA11684@uk.tiscali.com> <20051119050216.GU39882@cirb503493.alcatel.com.au> X-Mailer: Sylpheed-Claws 1.9.100 (GTK+ 2.8.6; i386-portbld-freebsd7.0) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Virus-Scanned: by amavisd-new Cc: freebsd-current@freebsd.org, Anderson , Eric, Brian Candler Subject: Re: Logical volume management X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 20 Nov 2005 12:59:30 -0000 On Sat, 19 Nov 2005 16:02:16 +1100 Peter Jeremy wrote: > The other disadvantages I see are: > - All the cylinder groups headers are pre-allocated. AFAIK, UFS2 avoids > pre-allocating the inodes but still reserves the space for them. A > large virtual filesystem will have significant overheads even if it > only has a small amount of real data. > - UFS assumes that all the space is physically available and allocates > blocks so as to (hopefully) maximize performance. This is likely to > lead to significant fragmentation with lots of partially utilised > data chunks. I think those are the reasons why Sun decided to integrate the "new" VM and the new FS code into one black box called ZFS (to prevent someone from using a plain UFS with the new VM and then moan because of the non-optimal performance). Bye, Alexander. -- Speak softly and carry a cellular phone. http://www.Leidinger.net Alexander @ Leidinger.net GPG fingerprint = C518 BC70 E67F 143F BE91 3365 79E2 9C60 B006 3FE7