From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda1.sgi.com [192.48.157.11]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id o4S0MP8l178900 for ; Thu, 27 May 2010 19:22:26 -0500 Received: from greer.hardwarefreak.com (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id EA1D8157D3A0 for ; Thu, 27 May 2010 17:26:42 -0700 (PDT) Received: from greer.hardwarefreak.com (mo-65-41-216-221.sta.embarqhsd.net [65.41.216.221]) by cuda.sgi.com with ESMTP id 1RlPDLq9U9jTY1hQ for ; Thu, 27 May 2010 17:26:42 -0700 (PDT) Received: from [192.168.100.53] (gffx.hardwarefreak.com [192.168.100.53]) by greer.hardwarefreak.com (Postfix) with ESMTP id 999B06C2B0 for ; Thu, 27 May 2010 19:24:48 -0500 (CDT) Message-ID: <4BFF0D94.5030903@hardwarefreak.com> Date: Thu, 27 May 2010 19:25:56 -0500 From: Stan Hoeppner MIME-Version: 1.0 Subject: Re: NOW: o_direct -- WAS: Re: WARNING in xfs_lwr.c, xfs_write() 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> In-Reply-To: <20100527114736.GA13112@infradead.org> 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: xfs@oss.sgi.com Christoph Hellwig put forth on 5/27/2010 6:47 AM: > 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. > > I have no idea why the MTAs don't want to use it - it's generally easier > to use then memory mapped I/O, and has much more deterministic > performance. Thanks for the background Christoph. I can now see why Postfix and Dovecot in particular don't use O_DIRECT: portability. They both are developed to run on every Unix/like OS you mention above, half of which don't offer O_DIRECT. I'm guessing the same may likely be true for the other SMTP MTAs and IMAP servers. -- Stan _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs