From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay3.corp.sgi.com [198.149.34.15]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id o9PG9c8h245593 for ; Mon, 25 Oct 2010 11:09:39 -0500 Date: Mon, 25 Oct 2010 11:10:52 -0500 From: Geoffrey Wehrman Subject: Re: XFS journaling position Message-ID: <20101025161052.GC19425@sgi.com> References: <31c7e56286d37870011c17ee8e002760.squirrel@webmail.ics.forth.gr> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <31c7e56286d37870011c17ee8e002760.squirrel@webmail.ics.forth.gr> 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: klonatos@ics.forth.gr Cc: xfs@oss.sgi.com On Mon, Oct 25, 2010 at 08:26:04AM +0300, klonatos@ics.forth.gr wrote: | I have recently discovered that the default journalling position of | XFS is in the "middle" AG, if the log is internal (e.g. for 32 AGs | the journal will be placed at the AG = 16). Although I am aware that | there is possible to explicitly specify a journal location using the | -l agnum=X mkfs option, I am really curious about the resoning behind | the default choice. I haven't found any documentation to support this, but I have been told that the middle was selected for the single disk case to minimize seek times. The distance the head must travel to or from other locations on the disk is optimized by placing the log in the middle of the disk. -- Geoffrey Wehrman SGI Building 10 Office: (651)683-5496 2750 Blue Water Road Fax: (651)683-5098 Eagan, MN 55121 E-mail: gwehrman@sgi.com http://www.sgi.com/products/storage/software/ _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs