From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: with ECARTIS (v1.0.0; list xfs); Mon, 16 Jul 2007 17:12:33 -0700 (PDT) Received: from mx2.suse.de (cantor2.suse.de [195.135.220.15]) by oss.sgi.com (8.12.10/8.12.10/SuSE Linux 0.7) with ESMTP id l6H0CTbm009270 for ; Mon, 16 Jul 2007 17:12:30 -0700 From: Neil Brown Date: Tue, 17 Jul 2007 09:56:25 +1000 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <18076.1449.138328.66699@notabene.brown> Subject: Re: raid50 and 9TB volumes In-Reply-To: message from David Chinner on Tuesday July 17 References: <5d96567b0707160542t2144c382mbfe3da92f0990694@mail.gmail.com> <20070716130140.GC31489@sgi.com> <5d96567b0707160653m5951fac9v5a56bb4c92174d63@mail.gmail.com> <20070716221831.GE31489@sgi.com> Sender: xfs-bounce@oss.sgi.com Errors-to: xfs-bounce@oss.sgi.com List-Id: xfs To: David Chinner Cc: Raz , xfs-oss On Tuesday July 17, dgc@sgi.com wrote: > On Mon, Jul 16, 2007 at 04:53:22PM +0300, Raz wrote: > > > > Well you are right. /proc/partitions says: > > .... > > 8 241 488384001 sdp1 > > 9 1 3404964864 md1 > > 9 2 3418684416 md2 > > 9 3 6823647232 md3 > > > > while xfs formats md3 as 9 TB. > > If i am using LBD , what is the biggest size I can use on i386 ? > > Supposedly 16TB. 32bit x 4k page size = 16TB. Given that the size is > not being reported correctly, I'd say that this is probably not an > XFS issue. The next thing to check is how large an MD device you > can create correctly. > > Neil, do you know of any problems with > 8TB md devices on i386? Should work, but the amount of testing has been limited, and bugs have existed. Each component of a raid5 is limited to 2^32 K by the metadata, so that is 4TB. At 490GB, you are well under that. There should be no problem with a 3TB raid5, providing LBD has been selected. raid0 over 3TB devices should also be fine. There was a bug fixed in May this year that caused problem with md/raid0 was used over components larger than 4TB on a 32bit host, but that shouldn't affect you and it does suggest that someone had success with a very large raid0 once this bug was fixed. If XFS is given a 6.8TB devices and formats it as 9TB, then I would be looking at mkfs.xfs(??). NeilBrown