From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751036Ab1A2Fk1 (ORCPT ); Sat, 29 Jan 2011 00:40:27 -0500 Received: from ipmail07.adl2.internode.on.net ([150.101.137.131]:24361 "EHLO ipmail07.adl2.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1749667Ab1A2Fk0 (ORCPT ); Sat, 29 Jan 2011 00:40:26 -0500 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AkQFAJc1Q015LN5mgWdsb2JhbACWZY4eFgEBFiIkuwANhUIE Date: Sat, 29 Jan 2011 16:40:21 +1100 From: Dave Chinner To: david@lang.hm Cc: Stan Hoeppner , Linux Kernel , xfs@oss.sgi.com, Christoph Hellwig , Justin Piszcz , Alex Elder , Mark Lord Subject: Re: xfs: very slow after mount, very slow at umount Message-ID: <20110129054021.GB21311@dastard> References: <4D40EB2F.2050809@teksavvy.com> <4D418B57.1000501@teksavvy.com> <4D419765.4070805@teksavvy.com> <4D41CA16.8070001@hardwarefreak.com> <4D42056E.2050505@hardwarefreak.com> <20110128135629.GX21311@dastard> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jan 28, 2011 at 11:26:00AM -0800, david@lang.hm wrote: > On Sat, 29 Jan 2011, Dave Chinner wrote: > > >On Thu, Jan 27, 2011 at 06:09:58PM -0800, david@lang.hm wrote: > >>On Thu, 27 Jan 2011, Stan Hoeppner wrote: > >>>david@lang.hm put forth on 1/27/2011 2:11 PM: > >>> > >>>Picking the perfect mkfs.xfs parameters for a hardware RAID array can be > >>>somewhat of a black art, mainly because no two vendor arrays act or perform > >>>identically. > >> > >>if mkfs.xfs can figure out how to do the 'right thing' for md raid > >>arrays, can there be a mode where it asks the users for the same > >>information that it gets from the kernel? > > > >mkfs.xfs can get the information it needs directly from dm and md > >devices. However, when hardware RAID luns present themselves to the > >OS in an identical manner to single drives, how does mkfs tell the > >difference between a 2TB hardware RAID lun made up of 30x73GB drives > >and a single 2TB SATA drive? The person running mkfs should already > >know this little detail.... > > that's my point, the person running mkfs knows this information, and > can easily answer questions that mkfs asks (or provide this > information on the command line). but mkfs doesn't ask for this > infomation, instead it asks the user to define a whole bunch of > parameters that are not well understood. I'm going to be blunt - XFS is not a filesystem suited to use by clueless noobs. XFS is a highly complex filesystem designed for high end, high performance storage and therefore has the configurability and flexibility required by such environments. Hence I expect that anyone configuring an XFS filesystem for a production environments is a professional and has, at minimum, done their homework before they go fiddling with knobs. And we have a FAQ for a reason. ;) > An XFS guru can tell you > how to configure these parameters based on different hardware > layouts, but as long as it remains a 'back art' getting new people > up to speed is really hard. If this can be reduced down to > > is this a hardware raid device > if yes > how many drives are there > what raid type is used (linear, raid 0, 1, 5, 6, 10) > > and whatever questions are needed, it would _greatly_ improve the > quality of the settings that non-guru people end up using. As opposed to just making mkfs DTRT without needing to ask questions? If you really think an interactive mkfs-for-dummies script is necessary, then go ahead and write one - you don't need to modify mkfs at all to do it..... Cheers, Dave. -- Dave Chinner david@fromorbit.com