From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sat, 11 May 2002 14:15:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sat, 11 May 2002 14:15:25 -0400 Received: from eventhorizon.antefacto.net ([193.120.245.3]:26500 "EHLO eventhorizon.antefacto.net") by vger.kernel.org with ESMTP id ; Sat, 11 May 2002 14:15:23 -0400 Message-ID: <3CDD5F53.3080202@antefacto.com> Date: Sat, 11 May 2002 19:13:39 +0100 From: Padraig Brady User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.0rc1) Gecko/20020417 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Peter Chubb CC: Jeremy Andrews , linux-kernel@vger.kernel.org Subject: Re: [PATCH] remove 2TB block device limit In-Reply-To: <15579.16423.930012.986750@wombat.chubb.wattle.id.au> <20020510084713.43ce396e.jeremy@kerneltrap.org> <15580.7052.396951.568702@wombat.chubb.wattle.id.au> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org I found the following related graph from Mr. Cahalan very informative: http://www.cs.uml.edu/~acahalan/linux/ext2.gif I just might get around to updating/expanding it. Padraig. Peter Chubb wrote: >>>>>>"Jeremy" == Jeremy Andrews writes: >>>>> > > Jeremy> Peter, Out of curiousity, what then does the new filesystem > Jeremy> limit become, on a 64-bit system? Will all filesystems > Jeremy> support your changes? > > This depends on the file system. > See > http://www.gelato.unsw.edu.au/~peterc/lfs.html > (which I'm intending to update next week, after some testing to > check the new limits with my new code -- I found the 1TB limit in > the generic code (someone using a signed int instead of unsigned long)) > > There are three different limits that apply: > > --- The physical layout on disc (e.g., ext2 uses 32-bit for block > numbers within a file system; thus the max size is > (2^32-1)*block_size; although it's theoretically possible to use > larger blocksizes, the current toolchain has a maximum of 4k, > thus the largest size of an ext[23] filesystem is ((2^32)-1)*4k > bytes --- around 16TB) > > It's extremely unlikely that you'd want to use a non-journalled > file system on such a large partition, so your best bets are > reiserfs, jfs or XFS. jfs and xfs work well on enormous > partitions on other platforms; the current version of reiserfs is > somewhat limited, but version 4 will allow larger file systems. > > > --- Limitations imposed by the partitioning scheme. > As far as I know, only the EFI GUID partitioning scheme uses > 64-bit block offsets, so under any other scheme you're limited to > 2^32 or 2^31 blocks per disc; some use the underlying hardware > sector size, some use a block size that's multiple of this. > > --- The page cache limit (which on a 32-bit system is 16TB; on a 64 > bit system is 18 EB > > > Jeremy> Mind if I quote what you say on my webpage? > > Go ahead > > -- > Peter Chubb > peterc@gelato.unsw.edu.au http://www.gelato.unsw.edu.au > -