From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda1.sgi.com [192.48.157.11]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id o5NALqj0019189 for ; Wed, 23 Jun 2010 05:21:54 -0500 Received: from one.firstfloor.org (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id AA78214AE670 for ; Wed, 23 Jun 2010 03:28:47 -0700 (PDT) Received: from one.firstfloor.org (one.firstfloor.org [213.235.205.2]) by cuda.sgi.com with ESMTP id KINHPGOSIWM65yr0 for ; Wed, 23 Jun 2010 03:28:47 -0700 (PDT) From: Andi Kleen Subject: Re: XFS peculiar behavior References: <4C21B9AF.9010307@ics.forth.gr> Date: Wed, 23 Jun 2010 12:24:27 +0200 In-Reply-To: <4C21B9AF.9010307@ics.forth.gr> (Yannis Klonatos's message of "Wed, 23 Jun 2010 10:37:19 +0300") Message-ID: <87bpb2avxg.fsf@basil.nowhere.org> MIME-Version: 1.0 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: Yannis Klonatos Cc: xfs@oss.sgi.com Yannis Klonatos writes: > The problem is that i have noticed that XFS may - not all Why is that a problem? > times - split a table over a large disk distance. For > example in one run i have noticed that a file of 13GByte is split over > a 4,7TByte distance (I calculate this distance > by subtracting the final block used for the file with the first > one. The two disk blocks values are acquired using the > FIBMAP ioctl). I don't know if it's the only reason, but XFS does a lot of data structure locking and updates per allocation group, so spreading to multiple AGs gives better scalability to many CPUs. Also I suppose it's good to avoid hot spots on the underlying device. -Andi -- ak@linux.intel.com -- Speaking for myself only. _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs