Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760598AbYBLXj1 (ORCPT ); Tue, 12 Feb 2008 18:39:27 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752917AbYBLXjS (ORCPT ); Tue, 12 Feb 2008 18:39:18 -0500 Received: from sovereign.computergmbh.de ([85.214.69.204]:47153 "EHLO sovereign.computergmbh.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751702AbYBLXjR (ORCPT ); Tue, 12 Feb 2008 18:39:17 -0500 Date: Wed, 13 Feb 2008 00:39:16 +0100 (CET) From: Jan Engelhardt To: David Miller cc: chris.mason@oracle.com, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, btrfs-devel@oss.oracle.com Subject: Re: BTRFS partition usage... In-Reply-To: <20080212.152652.217936905.davem@davemloft.net> Message-ID: References: <20080212.001104.172517283.davem@davemloft.net> <200802120849.34477.chris.mason@oracle.com> <20080212.152652.217936905.davem@davemloft.net> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1277 Lines: 32 On Feb 12 2008 15:26, David Miller wrote: > >> (Yes, I had xfs on sparc before, so it's not like you NEED the >> whitespace at the start of a partition.) > >You actully do unless you want to lose significant chunks of your disk >space. > >The Sun disk label only allows you to specify the start of a partition >in cylinders, so if you want to use a filesystem like XFS you have to >start the partition on cylinder 1 which can be many blocks into the >disk. That entire first cylinder is completely wasted. Ok you do have a point there. The GPT users win of course, since it uses LBA, not cyls, so the number of lost bytes is generally below a cyl. On the other hand, the H and S of CHS could be lowered and S increased, e.g. divide H by 2, divide S by 2, multiply S by 4. This gives a finer bytes/cylinder granularity. >What XFS does by putting the superblock at zero is simply does not >take these kinds of issues into consideration. > Well it was designed for a different system initially with a different style of booting. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/