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 o6L6piQX065840 for ; Wed, 21 Jul 2010 01:51:44 -0500 Received: from mail.internode.on.net (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 3FF4ABF7158 for ; Wed, 21 Jul 2010 00:01:28 -0700 (PDT) Received: from mail.internode.on.net (bld-mail14.adl6.internode.on.net [150.101.137.99]) by cuda.sgi.com with ESMTP id QoLOFQF5yr38A29H for ; Wed, 21 Jul 2010 00:01:28 -0700 (PDT) Date: Wed, 21 Jul 2010 16:54:29 +1000 From: Dave Chinner Subject: Re: Calculating swidth On A RAID6 Volume Message-ID: <20100721065429.GX32635@dastard> References: <3C5E029826A0704DB5998577FCFF46F0094DA1AD69@dagobah> <4C45AF09.5090901@dermichi.com> <20100720164444.4c1cef88@harpe.intellique.com> <201007201700.51977@zmi.at> <20100720172704.609477f4@harpe.intellique.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20100720172704.609477f4@harpe.intellique.com> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: Emmanuel Florac Cc: xfs@oss.sgi.com On Tue, Jul 20, 2010 at 05:27:04PM +0200, Emmanuel Florac wrote: > Le Tue, 20 Jul 2010 17:00:51 +0200 > Michael Monnerie =E9crivait: > = > > I'd say using su+sw is more future proof than swidth+sunit, as 4K > > sector drives will become standard, and then using 512B units will be > > outdated anyway, right? > = > Absolutely, and furthermore I'm wondering what's happening in the > case where the drives have 4096 bytes blocks; I suppose then sunit > should be expressed as a number of 4096 bytes blocks, and what about > swidth ? the hell if I know :) This is also probably a nice little nest > of coming filesystem bugs to be hatched :=3D) No, the sky is not going to fall. ;) The stripe unit is not related to sector size except for the fact that sector size defines the minimum filesystem block size and the stripe unit is an integer mutliple of the filesystem block size. i.e. mkfs.xfs -s size=3D512 -b size=3D512 -d sunit=3D1,swidth=3D1 is a valid configuration that gives single sector sunit/swidth alignment. Hence sunit needs to be able to express sizes in multiples of 512 bytes. For a 4k sector size drive, the equivalent is: mkfs.xfs -s size=3D4096 -b size=3D4096 -d sunit=3D8,swidth=3D8 and mkfs.xfs will ensure that any value of sunit that is not a multiple of 8 (4k) will be rejected..... Cheers, Dave. -- = Dave Chinner david@fromorbit.com _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs