From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda2.sgi.com [192.48.176.25]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id o2Q7Osxf208253 for ; Fri, 26 Mar 2010 02:24:54 -0500 Received: from omr15.networksolutionsemail.com (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 4871E279D58 for ; Fri, 26 Mar 2010 00:26:36 -0700 (PDT) Received: from omr15.networksolutionsemail.com (omr15.networksolutionsemail.com [205.178.146.65]) by cuda.sgi.com with ESMTP id 6syl7dY8fgEsZzTM for ; Fri, 26 Mar 2010 00:26:36 -0700 (PDT) Received: from cm-omr1 (mail.networksolutionsemail.com [205.178.146.50]) by omr15.networksolutionsemail.com (8.13.6/8.13.6) with ESMTP id o2Q7Qapw002859 for ; Fri, 26 Mar 2010 03:26:36 -0400 Message-ID: <4BAC61A4.6030607@chaven.com> Date: Fri, 26 Mar 2010 02:26:28 -0500 From: Steve Costaras MIME-Version: 1.0 Subject: Re: 128TB filesystem limit? References: <20100325235433.GM3335@dastard> <20100326003511.GN3335@dastard> <4BAC3990.30403@sandeen.net> In-Reply-To: List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: xfs@oss.sgi.com On 03/25/2010 23:56, david@lang.hm wrote: > On Thu, 25 Mar 2010, Eric Sandeen wrote: > >> david@lang.hm wrote: >>> On Fri, 26 Mar 2010, Dave Chinner wrote: >> >> ... >> >>>> Is there any reason for putting partitions on these block devices? >>>> You could just use the block devices without partitions, and that >>>> will avoid alignment potential problems.... >>> >>> I would like to raid to auto-assemble and I can't do that without >>> partitions, can I >> >> I think you can.... it's not like MD is putting anything in the >> partition >> table; you just give it block devices, I doubt it cares if it's a whole >> disk or some partition. >> >> Worth a check anyway ;) > > I know that md will work on raw devices, but the auto-assembly stuff > looks for the right partition type, I would have to maintain a conf > file across potential system rebuilds if I used the raw partitions. > >> ... >> >> >>> the next fun thing is figuring out what sort of stride, etc >>> parameters I >>> should have used for this filesystem. >> >> mkfs.xfs should suss that out for you automatically based on talking >> to md; >> of course you'd want to configure md to line up well with the hardware >> alignment. > > in this case md thinks it's working with 10 12.8TB drives, I really > doubt that it's going to do the right thing. > > I'm not exactly sure what the right thing is in this case. the > hardware raid is useing 64K chunks across 16 drives (so 14 * 64K worth > of data per stripe), but there are 10 of these stripes before you get > back to hitting the same drive again. > > David Lang > It does here at least, I never use partition tables on any of the arrays here just use LVM against what it sees as the 'raw' disk. I haven't tried it w/ a 128TB array but with smaller ones that's what I've used in the past (hw raid, md raid-0, file system). Recently for systems now I just use HW raid; LVM; and then filesystem (lvm does the striping/raid-0 function). when you create the physical volume w/ lvm just make sure you allign it (older versions use --metadatasize to 'pad' the start offset), newer versions have the dataalignment option. Steve _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs