From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Sandeen Subject: Re: [ext4] Documentation patch Date: Sun, 07 Dec 2008 14:43:28 -0600 Message-ID: <493C3570.4040100@redhat.com> References: <8763m3u9kv.fsf@basilikum.skogtun.org> <20081201165700.GA26680@infradead.org> <493425DC.1010008@redhat.com> <20081201205828.GA20069@mit.edu> <20081206222534.GJ1323@mit.edu> <493B0BAD.10004@redhat.com> <20081207183916.GB15998@mit.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit To: Theodore Tso , Eric Sandeen , Christoph Hellwig , Harald Arnesen , linux-kernel@vger.kernel.org, linux- Return-path: Received: from mx2.redhat.com ([66.187.237.31]:33506 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751471AbYLGUnz (ORCPT ); Sun, 7 Dec 2008 15:43:55 -0500 In-Reply-To: <20081207183916.GB15998@mit.edu> Sender: linux-ext4-owner@vger.kernel.org List-ID: Theodore Tso wrote: > Good points. OK, how about this? > > - When comparing performance with other filesystems, it's always > important to try multiple workloads; very often a subtle change in a > workload parameter can completely change the ranking of which > filesystems do well compared to others. When comparing versus ext3, > note that ext4 enables write barriers by default, while ext3 does > not enable write barriers by default. So it is useful to use > explicitly specify whether barriers are enabled or not when via the > '-o barriers=[0|1]' mount option for both ext3 and ext4 filesystems > for a fair comparison. When tuning ext3 for best benchmark numbers, > it is often worthwhile to try changing the data journaling mode; '-o > data=writeback,nobh' can be faster for some workloads. (Note > however that running mounting with data=writeback can potentially I'd say "running mounted with data=writeback...." other than that it looks good to me :) (sorta nitpicky but it probably won't be touched again for 5 years so may as well get it right now) :) -Eric > leave stale data exposed in recently written files in case of an > unclean shutdown, which could be a security exposure in some > situations.) Configuring the filesystem with a large journal can > also be helpful for metadata-intensive workloads. > > - Ted