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 n9J3s8gS025484 for ; Sun, 18 Oct 2009 22:54:08 -0500 Received: from bombadil.infradead.org (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 9C498A94553 for ; Sun, 18 Oct 2009 20:55:41 -0700 (PDT) Received: from bombadil.infradead.org (bombadil.infradead.org [18.85.46.34]) by cuda.sgi.com with ESMTP id ewvjz8jYLO52hqgf for ; Sun, 18 Oct 2009 20:55:41 -0700 (PDT) Date: Sun, 18 Oct 2009 23:55:38 -0400 From: Christoph Hellwig Subject: Re: XFS mount failuer on RAID5 Message-ID: <20091019035538.GC18296@infradead.org> References: <389deec70910152009i7656aaf2s9d929b8b68e4e740@mail.gmail.com> <200910161019.10286@zmi.at> <4AD890D1.4010208@sandeen.net> <200910172327.05122@zmi.at> <20091019013018.GQ9464@discord.disaster> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20091019013018.GQ9464@discord.disaster> 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: Dave Chinner Cc: Michael Monnerie , xfs@oss.sgi.com On Mon, Oct 19, 2009 at 12:30:18PM +1100, Dave Chinner wrote: > > IIRC, the main reason for 4k sectors on MD RAID5/6 is that changing > the IO alignment from 4k to 512 byte IOs (i.e. sub-page sized) > causes MD to flush and invalidate the stripe cache. Hence every > time XFS writes a super block, AGF, AGFL or AGI, things go much > slower because of this flush/invalidate. By setting the sector size > to 4k, the SB/AGF/AGFL/AGI are all 4k in size and hence IO alignment This should not happen anymore with 2.6 series kernels. _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs