From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda3.sgi.com [192.48.176.15]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id n7HLfBmH094869 for ; Mon, 17 Aug 2009 16:41:26 -0500 Received: from bombadil.infradead.org (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id B0EEF1BDADFA for ; Mon, 17 Aug 2009 14:41:38 -0700 (PDT) Received: from bombadil.infradead.org (bombadil.infradead.org [18.85.46.34]) by cuda.sgi.com with ESMTP id lasE1JBSWWX92MHg for ; Mon, 17 Aug 2009 14:41:38 -0700 (PDT) Date: Mon, 17 Aug 2009 17:41:36 -0400 From: Christoph Hellwig Subject: Re: disk performance strange/low Message-ID: <20090817214136.GA26060@infradead.org> References: <200908172311.07660@zmi.at> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <200908172311.07660@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: Michael Monnerie Cc: xfs@oss.sgi.com On Mon, Aug 17, 2009 at 11:11:07PM +0200, Michael Monnerie wrote: > I've got an Areca RAID Controller with 5x 1TB disks, and in the last > time I often found it to be strange. Now I investigated, and found this. > >From another server I NFS mount a share, and make > dd if=/dev/sda of=/server/share/test.dd bs=1024k > so that should do big sequential writes. But the performance goes up and > down, like you see in this output from "iostat -kx 5 555". You see write > KB/s is 5824, 23207, 87283, 704, 40187. Up and down all the time. Could > that be solved by the patch you discussed last time, or is there > something else? Yes, that sounds like the problem of the VM not feeding us enough pages to write. What kernel is this on? Latest 2.6.31-rc has a workaround for it. _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs