From: Eric Sandeen Subject: Re: [PATCH] Clustering indirect blocks in Ext3 (was Ext2) Date: Fri, 25 Apr 2008 10:54:30 -0500 Message-ID: <4811FEB6.60209@redhat.com> References: <4810F749.7000802@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Andreas Dilger , linux-ext4@vger.kernel.org To: Abhishek Rai Return-path: Received: from mx1.redhat.com ([66.187.233.31]:58590 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755862AbYDYPyg (ORCPT ); Fri, 25 Apr 2008 11:54:36 -0400 In-Reply-To: <4810F749.7000802@redhat.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: Eric Sandeen wrote: > Abhishek Rai wrote: >> This patch modifies the block allocation strategy in ext3 in order to >> improve fsck performance. This was initially sent out as a patch for >> ext2, but given the lack of ongoing development on ext2, I have >> crossported it to ext3 instead. Slow fsck is not a serious problem on >> ext3 due to journaling, but once in a while users do need to run full >> fsck on their ext3 file systems. This can be due to several reasons: >> (1) bad disk, bad crash, etc, (2) bug in jbd/ext3, and (3) every few >> reboots, it's good to run fsck anyway. This patch will help reduce >> full fsck time for ext3. I've seen 50-65% reduction in fsck time when >> using this patch on a near-full file system. With some fsck >> optimizations, this figure becomes 80%. > > For what it's worth, this speeds large file removals, too: > > http://people.redhat.com/esandeen/rm_test/ext3_metacluster_rm.png > http://people.redhat.com/esandeen/rm_test/ext3_rm.png Or, for more direct comparison: http://people.redhat.com/esandeen/rm_test/ext3_rm_stock_vs_metacluster.png -Eric