From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay1.corp.sgi.com [137.38.102.111]) by oss.sgi.com (Postfix) with ESMTP id F147C7F3F for ; Wed, 23 Apr 2014 03:26:11 -0500 (CDT) Received: from cuda.sgi.com (cuda1.sgi.com [192.48.157.11]) by relay1.corp.sgi.com (Postfix) with ESMTP id B77EA8F8039 for ; Wed, 23 Apr 2014 01:26:08 -0700 (PDT) Received: from ipmail04.adl6.internode.on.net (ipmail04.adl6.internode.on.net [150.101.137.141]) by cuda.sgi.com with ESMTP id UhqPQnWWDWGf1TyJ for ; Wed, 23 Apr 2014 01:26:06 -0700 (PDT) Date: Wed, 23 Apr 2014 18:25:38 +1000 From: Dave Chinner Subject: Re: rm -f * on large files very slow on XFS + MD RAID 6 volume of 15x 4TB of HDDs (52TB) Message-ID: <20140423082538.GR18672@dastard> References: <20140423021835.GI15995@dastard> <53576A7D.9020303@gmail.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <53576A7D.9020303@gmail.com> 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 Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com To: Ivan Pantovic Cc: linux-kernel@vger.kernel.org, Speedy Milan , xfs@oss.sgi.com On Wed, Apr 23, 2014 at 09:23:41AM +0200, Ivan Pantovic wrote: > > >[root@drive-b ~]# xfs_db -r /dev/md0 > >xfs_db> frag > >actual 11157932, ideal 11015175, fragmentation factor 1.28% > >xfs_db> > > this is current level of fragmentation ... is it bad? http://xfs.org/index.php/XFS_FAQ#Q:_The_xfs_db_.22frag.22_command_says_I.27m_over_50.25._Is_that_bad.3F > some say over 1% is candidate for defrag? ... Some say that over 70% is usually not a problem: http://www.mythtv.org/wiki/XFS_Filesystem#Defragmenting_XFS_Partitions i.e. the level that becomes are problem is highly workload specific. So, you can't read *anything* in that number without know exactly what is in your filesystem, how the application(s) interact with it and so on. Besides, I was asking specifically about the files you removed, not the files that remain in the filesystem. Given that you have 11 million inodes in the filesystem, you probably removed the only significantly large files in the filesystem.... So, the files your removed are now free space, so free space fragmentation is what we need to look at. i.e. use the freesp command to dump the histogram and summary of the free space... Cheers, Dave. -- Dave Chinner david@fromorbit.com _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932287AbaDWI0J (ORCPT ); Wed, 23 Apr 2014 04:26:09 -0400 Received: from ipmail04.adl6.internode.on.net ([150.101.137.141]:7310 "EHLO ipmail04.adl6.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755203AbaDWI0H (ORCPT ); Wed, 23 Apr 2014 04:26:07 -0400 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: Ao94AOF4V1N5LEcvPGdsb2JhbAA/GoMGT4MVqAMGlAmFYoEWFwMBAQEBODWCJQEBBAE6HCMFCwgDDgoJJQ8FJQMHGhMJiDAHDjbPDxaOQgeEOQSYdJRIgVEr Date: Wed, 23 Apr 2014 18:25:38 +1000 From: Dave Chinner To: Ivan Pantovic Cc: Speedy Milan , linux-kernel@vger.kernel.org, xfs@oss.sgi.com Subject: Re: rm -f * on large files very slow on XFS + MD RAID 6 volume of 15x 4TB of HDDs (52TB) Message-ID: <20140423082538.GR18672@dastard> References: <20140423021835.GI15995@dastard> <53576A7D.9020303@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <53576A7D.9020303@gmail.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 23, 2014 at 09:23:41AM +0200, Ivan Pantovic wrote: > > >[root@drive-b ~]# xfs_db -r /dev/md0 > >xfs_db> frag > >actual 11157932, ideal 11015175, fragmentation factor 1.28% > >xfs_db> > > this is current level of fragmentation ... is it bad? http://xfs.org/index.php/XFS_FAQ#Q:_The_xfs_db_.22frag.22_command_says_I.27m_over_50.25._Is_that_bad.3F > some say over 1% is candidate for defrag? ... Some say that over 70% is usually not a problem: http://www.mythtv.org/wiki/XFS_Filesystem#Defragmenting_XFS_Partitions i.e. the level that becomes are problem is highly workload specific. So, you can't read *anything* in that number without know exactly what is in your filesystem, how the application(s) interact with it and so on. Besides, I was asking specifically about the files you removed, not the files that remain in the filesystem. Given that you have 11 million inodes in the filesystem, you probably removed the only significantly large files in the filesystem.... So, the files your removed are now free space, so free space fragmentation is what we need to look at. i.e. use the freesp command to dump the histogram and summary of the free space... Cheers, Dave. -- Dave Chinner david@fromorbit.com