From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay1.corp.sgi.com [137.38.102.111]) by oss.sgi.com (Postfix) with ESMTP id 7F3277F37 for ; Wed, 13 Mar 2013 18:57:10 -0500 (CDT) Received: from cuda.sgi.com (cuda1.sgi.com [192.48.157.11]) by relay1.corp.sgi.com (Postfix) with ESMTP id 44B238F8059 for ; Wed, 13 Mar 2013 16:57:07 -0700 (PDT) Received: from ipmail04.adl6.internode.on.net (ipmail04.adl6.internode.on.net [150.101.137.141]) by cuda.sgi.com with ESMTP id 18XQfuuGCEp0oNm7 for ; Wed, 13 Mar 2013 16:57:05 -0700 (PDT) Date: Thu, 14 Mar 2013 10:57:03 +1100 From: Dave Chinner Subject: Re: xfs_fsr, sunit, and swidth Message-ID: <20130313235703.GX21651@dastard> References: <5140C147.7070205@binghamton.edu> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <5140C147.7070205@binghamton.edu> 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 Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com To: Dave Hall Cc: xfs@oss.sgi.com On Wed, Mar 13, 2013 at 02:11:19PM -0400, Dave Hall wrote: > Does xfs_fsr react in any way to the sunit and swidth attributes of > the file system? Not directly. > In other words, with an XFS filesytem set up > directly on a hardware RAID, it is recommended that the mount > command be changed to specify sunit and swidth values that reflect > the new geometry of the RAID. The mount option does nothing if sunit/swidth weren't specified at mkfs time. sunit/swidth affect the initial layout of the filesystem, and that cannot be altered after the fact. Hence you can't arbitrarily change sunit/swidth after mkfs - you are limited to changes that are compatible with the existing alignment. If you have no alignment specified, then there isn't a new alignment that can be verified as compatible with the existing layout..... > In my case, these values were not > specified on the mkfs.xfs of a rather large file system running on a > RAID 6 array. Which means the mount option won't work. > I am wondering adding sunit and swidth parameters to > the fstab will cause xfs_fsr to do anything different than it is > already doing. Most importantly, will it improve performace in any > way? It will make no difference at all. A more important question: why do you even need to run xfs_fsr? Cheers, Dave. -- Dave Chinner david@fromorbit.com _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs