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 p3RKY5Iv230695 for ; Wed, 27 Apr 2011 15:34:05 -0500 Received: from mail.sandeen.net (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 63E9F5115A4 for ; Wed, 27 Apr 2011 13:37:37 -0700 (PDT) Received: from mail.sandeen.net (sandeen.net [63.231.237.45]) by cuda.sgi.com with ESMTP id DOaqUCP85BKOPVkw for ; Wed, 27 Apr 2011 13:37:37 -0700 (PDT) Message-ID: <4DB87E90.9000103@sandeen.net> Date: Wed, 27 Apr 2011 15:37:36 -0500 From: Eric Sandeen MIME-Version: 1.0 Subject: Re: 2 question about XFS fragmentation and _fsr: SPLITTED Q1:sparse files References: <20110411214238.GE21395@dastard> <45DD2814B0C84BF3AFD76721A0178E50@myXP> <4DB87A19.30306@sandeen.net> In-Reply-To: <4DB87A19.30306@sandeen.net> 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: Janos Haar Cc: linux-xfs@oss.sgi.com On 4/27/11 3:18 PM, Eric Sandeen wrote: > On 4/26/11 4:51 PM, Janos Haar wrote: > > > >>>> In the result, actually we have >6TB images on the 3TB disk, wich is >>>> 97.9% fragmented. >>> >>> How are you determining that figure? >> >> [root@UNISTORE admin]# cat xfs_get_frat_ratio >> echo loop0 >> xfs_db -c frag -r /dev/loop0 >> [root@UNISTORE admin]# ./xfs_get_frat_ratio >> loop0 >> actual 7650952, ideal 752501, fragmentation factor 90.16% btw we should just nuke that stupid command ;) > so you had 7650952 extents on the fs, ideally you'd have 752501, or so xfs_db says... > > Another way of looking at this is that you have about 10 extents per file on average. > > Depending on the size of the files, this may be perfectly fine. > Is, for example, a 10G file in ten 1G extents really a problem? > > I doubt that fragmentation is your performance problem here. ... note however that you can use xfs_bmap to examine the layout of any particular file. 10 on average may be 1 for most, and 10,000 for the last one. :) -Eric _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs