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 o3RFXFAa167064 for ; Tue, 27 Apr 2010 10:33:15 -0500 Received: from esri3.esri.com (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 7D617154DC62 for ; Tue, 27 Apr 2010 08:35:18 -0700 (PDT) Received: from esri3.esri.com (esrismtp2.esri.com [198.102.62.103]) by cuda.sgi.com with ESMTP id oUMu8LJBrw7Ml6u4 for ; Tue, 27 Apr 2010 08:35:18 -0700 (PDT) Date: Tue, 27 Apr 2010 08:35:04 -0700 From: Ray Van Dolson Subject: Re: O_SYNC behavior? Message-ID: <20100427153504.GA27787@esri.com> References: <20100426225627.GA7106@esri.com> <537687191.239471272324343715.JavaMail.root@mail-au.aconex.com> <20100427093250.GA15182@citd.de> <20100427141205.GA557@infradead.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20100427141205.GA557@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: Christoph Hellwig Cc: Nathan Scott , "xfs@oss.sgi.com" On Tue, Apr 27, 2010 at 07:12:05AM -0700, Christoph Hellwig wrote: > On Tue, Apr 27, 2010 at 11:32:50AM +0200, Matthias Schniedermeyer wrote: > > I don't think that answers the intented question. > > > > I guess the correct answer is: > > It depends on the server-side configuration. > > An "async" export gets the "done"-answer immediatly. > > An "sync" export (only when also mounted "sync" AFAIU) waits at least > > until the write command is send down the stack, maybe even until the > > data actually hit the platters or silicon in the SSD-case. > > > > man 5 exports: > > - snip - > > sync: Reply to requests only after the changes have been committed to stable storage > > - snip - > > > > But i guess the performance will be horrible when both side are "sync". > > The client side (that is mount-side) sync means implying O_SYNC for all > I/O - no need for that. And sync exports are the default for every sane > server. > Thanks guys. I was asking this from the perspective of a ZFS type setup with its intent log (ZIL) on SSD's or some battery backed NVRAM. In this setup, with sync mode NFS, acknowledgement is sent to the client as soon as the data is written to the ZIL -- before it actually hits the underlying disks. Just was trying to determine a way to mirror this setup with XFS. Thanks, Ray _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs