From: Trond Myklebust Subject: Re: Differences between 2.6.5 und 2.6.16: getattr with actimeo=0 and O_DIRECT Date: Tue, 13 Nov 2007 08:29:58 -0500 Message-ID: <1194960598.7468.11.camel@heimdal.trondhjem.org> References: <4739686E.8080501@googlemail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Cc: nfs@lists.sourceforge.net To: Gerd Bavendiek Return-path: Received: from sc8-sf-mx1-b.sourceforge.net ([10.3.1.91] helo=mail.sourceforge.net) by sc8-sf-list2-new.sourceforge.net with esmtp (Exim 4.43) id 1Irvpp-0007aB-L2 for nfs@lists.sourceforge.net; Tue, 13 Nov 2007 05:29:45 -0800 Received: from pat.uio.no ([129.240.10.15]) by mail.sourceforge.net with esmtps (TLSv1:AES256-SHA:256) (Exim 4.44) id 1Irvpt-0005i8-2A for nfs@lists.sourceforge.net; Tue, 13 Nov 2007 05:29:51 -0800 In-Reply-To: <4739686E.8080501@googlemail.com> List-Id: "Discussion of NFS under Linux development, interoperability, and testing." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: nfs-bounces@lists.sourceforge.net Errors-To: nfs-bounces@lists.sourceforge.net On Tue, 2007-11-13 at 10:03 +0100, Gerd Bavendiek wrote: > Hi, > > analyzing performance issues with Oracle databases on an NFS client > running on SLES9 SP3 and NetApp as NFS server, I found that in SLES9 > SP3 each write call is followed by an getattr. This is not the case > with SLES10 SP1. > > Mount options in use are: > > rw,v3,rsize=32768,wsize=32768,acregmin=0,acregmax=0,acdirmin=0,acdirmax=0,hard,lock,proto=tcp,addr=172.18.131.134 > > I do > > dd if=/dev/zero of=/mnt/qqq oflag=direct bs=8k count=100000 > > and using tcpdump (BTW, is there an easier way ?) I see with SLES9 SP3 > (i.e. 2.6.5-7.244) each single 8k write followed by an getattr (which > comes at some cost). > > Using SLES10 SP1 (2.6.16.46-0.12) there is only one getattr when dd > closes the file. > > Is there anything I can do to avoid the getattr calls in SLES9 SP3 > (no, sorry, can't update to SLES10 SP1) ? For one thing, you could turn attribute caching back on. I don't know why SLES10 fails to GETATTR, but acregmin=0,acregmax=0 turns attribute caching off. Append writes need to know where the end-of-file is, and so they will force a GETATTR when there is no attribute caching. Trond ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ NFS maillist - NFS@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/nfs