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 9D34F7CBE for ; Mon, 30 May 2016 03:49:50 -0500 (CDT) Received: from cuda.sgi.com (cuda2.sgi.com [192.48.176.25]) by relay3.corp.sgi.com (Postfix) with ESMTP id 25014AC003 for ; Mon, 30 May 2016 01:49:47 -0700 (PDT) Received: from mail-wm0-f45.google.com (mail-wm0-f45.google.com [74.125.82.45]) by cuda.sgi.com with ESMTP id JNNZUddL1qpnbtS2 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NO) for ; Mon, 30 May 2016 01:48:43 -0700 (PDT) Received: by mail-wm0-f45.google.com with SMTP id s131so14648417wme.0 for ; Mon, 30 May 2016 01:48:43 -0700 (PDT) Mime-Version: 1.0 (Mac OS X Mail 9.3 \(3124\)) Subject: Re: XFS: possible memory allocation deadlock in kmem_alloc From: baotiao In-Reply-To: <20160530050452.GM26977@dastard> Date: Mon, 30 May 2016 16:48:36 +0800 Message-Id: <9BD371B3-8A44-481C-B9E4-381BAE0B6B79@gmail.com> References: <20160530050452.GM26977@dastard> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: multipart/mixed; boundary="===============2419360255060093023==" Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com To: Dave Chinner Cc: xfs@oss.sgi.com --===============2419360255060093023== Content-Type: multipart/alternative; boundary="Apple-Mail=_3BE03A55-D45E-4B6C-AE01-71BB9508A0DD" --Apple-Mail=_3BE03A55-D45E-4B6C-AE01-71BB9508A0DD Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii how can I set the extent size hint to a file with command line?=20 I have google for a lot, but I can't find a answer ---------------------------------------- =20 Github: https://github.com/baotiao Blog: http://baotiao.github.io Stackoverflow: http://stackoverflow.com/users/634415/baotiao=20 Linkedin: http://www.linkedin.com/profile/view?id=3D145231990 > On May 30, 2016, at 13:04, Dave Chinner wrote: >=20 > 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 >>=20 >> [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 >=20 > 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. >=20 > .... >> actual 48421430, ideal 20716, fragmentation factor 99.96% >>=20 >> How can I solve this problem, what do you suggest me to do? >=20 > 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.=20 >=20 > Cheers, >=20 > Dave. > --=20 > Dave Chinner > david@fromorbit.com --Apple-Mail=_3BE03A55-D45E-4B6C-AE01-71BB9508A0DD Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=us-ascii how can I set the extent size hint to a file with command = line? 
I have google for a lot, but I can't find a = answer


On May 30, 2016, at 13:04, Dave Chinner <david@fromorbit.com>= wrote:

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

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