From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263784AbUEXBDq (ORCPT ); Sun, 23 May 2004 21:03:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263786AbUEXBDq (ORCPT ); Sun, 23 May 2004 21:03:46 -0400 Received: from mtvcafw.SGI.COM ([192.48.171.6]:41058 "EHLO omx2.sgi.com") by vger.kernel.org with ESMTP id S263784AbUEXBDo (ORCPT ); Sun, 23 May 2004 21:03:44 -0400 Date: Mon, 24 May 2004 11:00:59 +1000 From: Nathan Scott To: hch@infradead.org, Herbert Xu , Leonardo Macchia , 250477@bugs.debian.org, Neil Brown , Linux Kernel Mailing List Subject: Re: Bug#250477: kernel-source-2.4.26: Lots of debug in RAID5 Message-ID: <20040524110059.B751892@wobbly.melbourne.sgi.com> References: <20040523085801.2878013C002@nomade.ciram.unibo.it> <20040523105351.GB19402@gondor.apana.org.au> <20040523111622.GA24817@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <20040523111622.GA24817@infradead.org>; from hch@infradead.org on Sun, May 23, 2004 at 07:16:22AM -0400 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, May 23, 2004 at 07:16:22AM -0400, hch@infradead.org wrote: > On Sun, May 23, 2004 at 08:53:51PM +1000, Herbert Xu wrote: > > > --- kernel-source-2.4.26/drivers/md/raid5.c 2003-08-30 06:01:38.000000000 +0000 > > > +++ kernel-source-2.4.26-nodebug/drivers/md/raid5.c 2004-05-23 08:54:36.000000000 +0000 > > > @@ -282,7 +282,7 @@ > > > } > > > > > > if (conf->buffer_size != size) { > > > - printk("raid5: switching cache buffer size, %d --> %d\n", oldsize, size); > > > + PRINTK("raid5: switching cache buffer size, %d --> %d\n", oldsize, size); > > > shrink_stripe_cache(conf); > > > if (size==0) BUG(); > > > conf->buffer_size = size; > > > > Thanks for the patch. This does indeed look like a typo. > > > > Hi Neil, does this patch look OK to you? > > No, this was rejected a few times already. The problem is that XFS > uses differen I/O sizes for the log and other I/O which makes raid > performance suck really badly. The real fix is to use the v2 XFS log > format when using software raid5. What is really wanted is the -ssize=4096 option to mkfs.xfs. This does the 4k aligned log IO Christoph is talking about here, and also sizes a few other XFS ondisk structures such that there is no I/O to the device that is not 4K aligned. Neil, I wonder if we could make the message more informative? Maybe some words about a suboptimal filesystem configuration, or something to that effect. cheers. -- Nathan