From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756971Ab1LWNAg (ORCPT ); Fri, 23 Dec 2011 08:00:36 -0500 Received: from cantor2.suse.de ([195.135.220.15]:43647 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756892Ab1LWNAe (ORCPT ); Fri, 23 Dec 2011 08:00:34 -0500 Date: Fri, 23 Dec 2011 14:00:08 +0100 From: Jan Kara To: Simon Mcnair Cc: linux-kernel@vger.kernel.org Subject: Re: kernel Unaligned AIO/DIO on inode EXT4-fs Unaligned AIO/DIO on inode by VirtualBox; performance will be poor. Message-ID: <20111223130008.GA29095@quack.suse.cz> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Fri 23-12-11 09:42:08, Simon Mcnair wrote: > Sorry for the Newb question but I can't find much clarification of > what this means via google search. Having seen that it's a generic > kernel error message which just happens to be caused by Virtualbox, I > do not think that Virtualbox is the culprit ? > > Dec 20 09:27:24 simon-Vostro1510 kernel: [ 345.592265] EXT4-fs > (sda5): Unaligned AIO/DIO on inode 3408273 by VirtualBox; performance > will be poor. ... > > Linux simon-Vostro1510 3.0.0-14-generic #23-Ubuntu SMP Mon Nov 21 > 20:28:43 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux > > root@simon-Vostro1510:/home/simon/VirtualBox VMs/Win7 64bit# ls -lah > -rw------- 1 simon simon 116G 2011-12-22 20:12 Win7.vmdk > > Anything I can do to stop this message ?, a change in virtual disk > file from vmdk to VDI or ...something ? Well, kernel complains that VirtualBox is doing unaligned AIO/DIO. I suppose that it's caused by the fact that the filesystem in Win7.vmdk image has block size smaller than 4 KB but I'm not really sure how VirtualBox does IO. You should talk to VirtualBox guys whether you could tune your installation somehow so that VirtualBox works more efficiently. Honza