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 o3GAftCZ242557 for ; Fri, 16 Apr 2010 05:41:55 -0500 Received: from greer.hardwarefreak.com (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id A56A72C909C for ; Fri, 16 Apr 2010 03:43:50 -0700 (PDT) Received: from greer.hardwarefreak.com (mo-65-41-216-221.sta.embarqhsd.net [65.41.216.221]) by cuda.sgi.com with ESMTP id uSrOdPT3FCspO9bF for ; Fri, 16 Apr 2010 03:43:50 -0700 (PDT) Received: from [192.168.100.53] (gffx.hardwarefreak.com [192.168.100.53]) by greer.hardwarefreak.com (Postfix) with ESMTP id 5F4586C002 for ; Fri, 16 Apr 2010 05:43:50 -0500 (CDT) Message-ID: <4BC83F65.4040309@hardwarefreak.com> Date: Fri, 16 Apr 2010 05:43:49 -0500 From: Stan Hoeppner MIME-Version: 1.0 Subject: Re: xfs_fsr question for improvement References: <201004161043.11243@zmi.at> In-Reply-To: <201004161043.11243@zmi.at> 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: xfs@oss.sgi.com Michael Monnerie put forth on 4/16/2010 3:43 AM: > To prevent this, xfs_fsr should do a "compress" phase after > defragmentation finished, in order to move all the files behind each > other: > file 1GB > file 1GB > file 1GB > file 1GB > freespace 3600M > That would also help fill the filesystem from front to end, reducing > disk head moves. What happens if those are frequently written/appended files, such as logs or mbox mail files, database files, etc? If you pack them nose to tail with this "compress" phase they will instantly be fragmented upon the next append operation. Leaving some free sectors at the tail end of a file is what helps prevent fragmentation. I don't think this compression would be a good default behavior. I think "packing" is probably a better term as "compression" has a long standing connotation. Sounds like you have a corner case. If this "packing" was implemented, maybe it would be best to make it a command line option only. -- Stan _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs