From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: with ECARTIS (v1.0.0; list xfs); Tue, 05 Dec 2006 13:28:12 -0800 (PST) Received: from larry.melbourne.sgi.com (larry.melbourne.sgi.com [134.14.52.130]) by oss.sgi.com (8.12.10/8.12.10/SuSE Linux 0.7) with SMTP id kB5LS0aG009034 for ; Tue, 5 Dec 2006 13:28:02 -0800 Date: Wed, 6 Dec 2006 08:26:49 +1100 From: David Chinner Subject: Re: mkfs.xfs questions Message-ID: <20061205212649.GV44411608@melbourne.sgi.com> References: <20061129174553.e0ef3465.jasmin@pacifica.ch> <20061201183034.GA20595@teal.hq.k1024.org> <20061202111546.GA18661@teal.hq.k1024.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: xfs-bounce@oss.sgi.com Errors-to: xfs-bounce@oss.sgi.com List-Id: xfs To: Christian Kujau Cc: Iustin Pop , xfs@oss.sgi.com, jasmin@pacifica.ch On Tue, Dec 05, 2006 at 05:46:15PM +0000, Christian Kujau wrote: > On Sat, 2 Dec 2006, Iustin Pop wrote: > >Hmm, I am pretty sure that it makes a difference, but only from personal > >experience, not from benchmarks. A while ago, mkfs.xfs used to make <8M > >logs even for big filesystems[0]. Nowadays it chooses a more sane value. > > I could not stand my own curiosity, so here it is: > http://nerdbynature.de/wp/?cat=4 One line summary: "The results however are a bit boring and I for one have no reason to tweak these options for a desktop machine." For that data set size you tested. However you might find a difference if your tests actually write the data back to disk because a lot of the tests are running out of cache. > I think I'll repeat the benchmarks with bigger test sizes. The > testscript can easily be adjusted to test more options/values. I think you need to to have any hope of demonstrating a difference in performance from the mkfs/mount options. Typically, you need to be writing/reading files at least 2x the size of memory and create/delete a fileset of at least 1,000,000 files to really determine differences in performance from these parameters... Cheers, Dave. -- Dave Chinner Principal Engineer SGI Australian Software Group