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 p59LHZ0g201179 for ; Thu, 9 Jun 2011 16:17:36 -0500 Received: from ipmail06.adl6.internode.on.net (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id EC27C1665C50 for ; Thu, 9 Jun 2011 14:17:34 -0700 (PDT) Received: from ipmail06.adl6.internode.on.net (ipmail06.adl6.internode.on.net [150.101.137.145]) by cuda.sgi.com with ESMTP id ulBJlZkdlUZBozNE for ; Thu, 09 Jun 2011 14:17:34 -0700 (PDT) Date: Fri, 10 Jun 2011 07:17:31 +1000 From: Dave Chinner Subject: Re: Small files perform much faster on newly formatted fs? Message-ID: <20110609211731.GT32466@dastard> References: <20110607163742.GH28625@pyre.virge.net> <201106080911.11286@zmi.at> <20110608122638.GQ28625@pyre.virge.net> <20110609012907.GR32466@dastard> <20110609134811.GI28625@pyre.virge.net> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20110609134811.GI28625@pyre.virge.net> 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: Norbert Veber Cc: Michael Monnerie , xfs@oss.sgi.com On Thu, Jun 09, 2011 at 09:48:11AM -0400, Norbert Veber wrote: > On Thu, Jun 09, 2011 at 11:29:07AM +1000, Dave Chinner wrote: > > Those mount options are ignored if the filesystem doesn't have the > > superblock feature bit set for aligned allocations. A filesystem > > with 0/0 for sunit/swidth does not have the superblock bit set.... > > Oh man! I thought I saw some improvement with iometer benchmarks before > and after the mount options, but I dont see any significant difference > while timing the untar and rm -rf I've been doing. > > All the documentation I came across including the man page and XFS faq > entry imply that the mount options can be used to perform alignment.. The mount options are only there to cahnge the alignment that already exists, and there are significant limitations on those changes. You can't just apply alignment to a filesystem with no alignment becaue XFS makes certain assumptions about how aligned filesystems are laid out (e.g. AGs always start aligned to a sunit). If the filesystem is created without alignment, there is a pretty good chance that it is simply not possible to post-apply alignment to it. > In these kinds of cases maybe there should be an error logged instead of > just silently ignoring them? It does log errors if you already have alignment set and your change is invalid. If you don't have alignemnt, then they are no-ops and so are ignored. > Is there any way to change the superblock? Eg. soething like the ext* > command: You can do it with xfs_db, but see above for why it's a bad idea. Cheers, Dave. -- Dave Chinner david@fromorbit.com _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs