From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda2.sgi.com [192.48.176.25]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id o4RDuZ1h137460 for ; Thu, 27 May 2010 08:56:35 -0500 Received: from kaylee.flamingspork.com (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 4DB6737BD7D for ; Thu, 27 May 2010 06:58:57 -0700 (PDT) Received: from kaylee.flamingspork.com (kaylee.flamingspork.com [74.207.245.61]) by cuda.sgi.com with ESMTP id uLRpdjx3vhmDSW28 for ; Thu, 27 May 2010 06:58:57 -0700 (PDT) From: Stewart Smith Subject: Re: NOW: o_direct -- WAS: Re: WARNING in xfs_lwr.c, xfs_write() In-Reply-To: <20100527114736.GA13112@infradead.org> References: <20100523002023.41f5a5c8@aaa.pulp.binarylife.net> <20100523101856.GL2150@dastard> <20100523092344.0fcaab42@aaa.pulp.binarylife.net> <4BF9FCA8.8090906@hardwarefreak.com> <20100524143428.6f3a117c@abend.internal.xtremedata.com> <20100526070620.GT2150@dastard> <4BFD3926.6040208@hardwarefreak.com> <20100527114736.GA13112@infradead.org> Date: Thu, 27 May 2010 23:58:55 +1000 Message-ID: <87pr0hbg4g.fsf@willster.local.flamingspork.com> MIME-Version: 1.0 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: Christoph Hellwig , Stan Hoeppner Cc: xfs@oss.sgi.com On Thu, 27 May 2010 07:47:37 -0400, Christoph Hellwig wrote: > O_DIRECT is not a Posix standard and not very portable. It originated > on IRIX, and Linux inherited it during the 2.4 kernel series days. > These days FreeBSD/NetBSD and AIX support it as well, but for example > Solaris, HP-UX and OpenBSD don't, nevermind Windows or Mac OS. There is O_DIRECT type functionality available on Windows, with similar restrictions for aligned IO too. You have to use the Win32 APIs to do it though, the POSIX ones won't get you it (or more than 2048 files open at once). In practice we've only ever found Solaris (other than linux) to be reliable with O_DIRECT (at least on UFS... ZFS is... well... I wouldn't run a database server on it yet). -- Stewart Smith _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs