From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda2.sgi.com [192.48.176.25]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id o7BNi9Rl169518 for ; Wed, 11 Aug 2010 18:44:09 -0500 Received: from mail.internode.on.net (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 1E1154AD3CD for ; Wed, 11 Aug 2010 16:44:32 -0700 (PDT) Received: from mail.internode.on.net (bld-mail19.adl2.internode.on.net [150.101.137.104]) by cuda.sgi.com with ESMTP id FOQTEyL8CCQtgPsF for ; Wed, 11 Aug 2010 16:44:32 -0700 (PDT) Date: Thu, 12 Aug 2010 09:44:20 +1000 From: Dave Chinner Subject: Re: observed significant performance improvement using "delaylog" in a real-world application Message-ID: <20100811234420.GA10429@dastard> References: <201008111003.36890@zmi.at> <201008111428.31196@zmi.at> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: 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: Peter Niemayer Cc: linux-xfs@oss.sgi.com On Wed, Aug 11, 2010 at 07:01:31PM +0200, Peter Niemayer wrote: > On 08/11/2010 02:28 PM, Michael Monnerie wrote: > >Thank you. Are those files located within one dir or do you use a hash > >structure like squid cache does? > > There's only a shallow hierarchy (for functional, not for distribution > reasons), so the relevant directories have thousands of files in them. > > I think after the "ext2"-age no serious file system ever had > a real problem dealing with lots of files in one directory - > or do you have contradicting information? Define "lots of files". :) >>From my numbers, ext3/4 still fall way behind XFS and btrfs when it comes to handling directories with tens of thousands of entries or larger. Especially on cold-cache random lookups. XFS also has quite sophisticated internal directory readahead, so under the cold cache directory performance of XFS is far better than ext3/4 can acheive, even for relatively small directories. IIRC this difference in directory lookup performance was one of the prime reasons kernel.org switched from ext3 to XFS a couple of years back... Cheers, Dave. -- Dave Chinner david@fromorbit.com _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs