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 (Postfix) with ESMTP id 574977CB2 for ; Mon, 30 May 2016 00:05:40 -0500 (CDT) Received: from cuda.sgi.com (cuda2.sgi.com [192.48.176.25]) by relay3.corp.sgi.com (Postfix) with ESMTP id C5843AC002 for ; Sun, 29 May 2016 22:05:36 -0700 (PDT) Received: from ipmail05.adl6.internode.on.net (ipmail05.adl6.internode.on.net [150.101.137.143]) by cuda.sgi.com with ESMTP id 05uqTGAGV8dfURro for ; Sun, 29 May 2016 22:05:33 -0700 (PDT) Date: Mon, 30 May 2016 15:04:52 +1000 From: Dave Chinner Subject: Re: XFS: possible memory allocation deadlock in kmem_alloc Message-ID: <20160530050452.GM26977@dastard> References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: 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 Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com To: baotiao Cc: xfs@oss.sgi.com On Mon, May 30, 2016 at 12:45:07PM +0800, baotiao wrote: > This machine is running for qemu, the file is qemu qcow file type > > [root@w-openstack20 /data/nova/instances/7898b630-c4ef-49ab-9ce9-3735e090c282]# file disk > disk: QEMU QCOW Image (v3), has backing file (path /data/nova/instances/_base/3f27393376152ac352b2d85703011e38517e), 429496729600 bytes Oh, you're using delta/snapshot based qcow images. That, by it's very nature, generates fragmented image files as they are a delta over the backing file. .... > actual 48421430, ideal 20716, fragmentation factor 99.96% > > How can I solve this problem, what do you suggest me to do? Use a extent size hint (say 1-8MB) for your qcow2 image files so that they don't fragment badly as they are written to. Cheers, Dave. -- Dave Chinner david@fromorbit.com _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs