From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda1.sgi.com [192.48.157.11]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id q0KC6hQv102374 for ; Fri, 20 Jan 2012 06:06:43 -0600 Received: from honeysuckle.london.02.net (honeysuckle.london.02.net [87.194.255.144]) by cuda.sgi.com with ESMTP id YmsZTS5TqPbhiV2F for ; Fri, 20 Jan 2012 04:06:39 -0800 (PST) Received: from ty.sabi.co.UK (87.194.99.40) by honeysuckle.london.02.net (8.5.140) id 4EEF52D2008B2074 for xfs@oss.sgi.com; Fri, 20 Jan 2012 12:06:37 +0000 Received: from from [127.0.0.1] (helo=tree.ty.sabi.co.UK) by ty.sabi.co.UK with esmtp(Exim 4.71 #1) id 1RoDEl-0004HT-Fy for ; Fri, 20 Jan 2012 12:06:31 +0000 MIME-Version: 1.0 Message-ID: <20249.22727.359884.733592@tree.ty.sabi.co.UK> Date: Fri, 20 Jan 2012 12:06:31 +0000 Subject: Re: Optimal XFS formatting options? In-Reply-To: <4F192DEC.4030400@tlinx.org> References: <33140169.post@talk.nabble.com> <20242.10382.19330.275280@tree.ty.sabi.co.UK> <4F192DEC.4030400@tlinx.org> From: pg_xf2@xf2.for.sabi.co.UK (Peter Grandi) List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: Linux fs XFS [ ... ] >> * XFS has several limitations on 32b kernels. Just make sure >> you have a 64b kernel. [ ... ] > I was unaware that the block size was larger on 64b kernels. > Is that what you are referring to ? (would be nice)... Not as such, the maximum block size is limited by the Linux page cache, that is hw page size, which is for IA32 and AMD64 architectures the same at 4KiB. However other architectures which are natively 64b allow bigger page sizes (notably IA64 [aka Itanium]), so the page cache and thus XFS can do larger blocks sizes. The limitations of XFS on 32b kernels come from limitations of XFS itself in 32b mode, limitations of Linux in 32b mode, and combined limitations. For example: * There be 32b inode numbers, which limit inodes to the first 1TB of a filetree if sector size is 512B. * The 32b block IO subsystems limits partition sizes to 16TiB. * XFS tools scanning a large filesystem, usually for repair, can run out of the available 32b address space (by default around 2GiB). Page 5 and 6 here list some limits: http://oss.sgi.com/projects/xfs/training/xfs_slides_02_overview.pdf _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs