From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yusuf Goolamabbas Subject: Re: Should NFS over loopback be over 10x slower compared to local fs Date: Tue, 30 Mar 2004 11:04:29 +0800 Sender: nfs-admin@lists.sourceforge.net Message-ID: <20040330030429.GA26484@outblaze.com> References: <20040329042504.GE14714@outblaze.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: nfs@lists.sourceforge.net, akpm@osdl.org Return-path: Received: from sc8-sf-mx2-b.sourceforge.net ([10.3.1.12] helo=sc8-sf-mx2.sourceforge.net) by sc8-sf-list2.sourceforge.net with esmtp (Exim 4.30) id 1B89YH-0002cc-1T for nfs@lists.sourceforge.net; Mon, 29 Mar 2004 19:04:33 -0800 Received: from corpmail.outblaze.com ([203.86.166.82]) by sc8-sf-mx2.sourceforge.net with esmtp (Exim 4.30) id 1B89YG-0004la-Jl for nfs@lists.sourceforge.net; Mon, 29 Mar 2004 19:04:32 -0800 Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by corpmail.outblaze.com (Postfix) with ESMTP id 162DB37AFF for ; Tue, 30 Mar 2004 03:04:32 +0000 (GMT) Received: from yusufg.portal2.com (210-177-227-130.outblaze.com [210.177.227.130]) by corpmail.outblaze.com (Postfix) with SMTP id 3EDBF16DD8B for ; Tue, 30 Mar 2004 03:04:31 +0000 (GMT) To: Matthias Andree In-Reply-To: Errors-To: nfs-admin@lists.sourceforge.net List-Unsubscribe: , List-Id: Discussion of NFS under Linux development, interoperability, and testing. List-Post: List-Help: List-Subscribe: , List-Archive: > > Hi, I did a postmark run on a local ext3 filesystem (data=writeback) and > > then compared it with the same filesystem mounted over loopback and then > > over a 100Mbit switch, I see a dramatic slowdown with postmark numbers > > of loopback NFS compared to local fs. > > Depending on drive speed and write clustering, expect a significant > slowdown I'm not sure 10x is OK, but it's certainly realistic. I expected a slowdown, it's just that I felt that 10x was inappropiate. Curious as to what others get with the same test run on different OS/hardware On FreeBSD 4.9-RELEASE on similar hardware, the slowdown is only half compared to postmark over local softupdate enabled fs. Also on 2.6.x, NFS over loopback wasn't that much faster than NFS over 100Mbit > There's an important difference between NFS and local file system, in > semantics: Once the NFS server has acknowledged the _write_ request, the > data is on disk. You don't get that sort of guarantee with a local file > system unless you open with O_SYNC (and I wonder how many bugs > "not-quite-synchronous" need to be shaken out WRT local file systems > given the recent fsync() discussion). Hmm, That's plausible. I did a tiobench run over a local ext3 fs (data=writeback) and the same run over loopback NFS and the slowdown was in sequential/random writes though sequential writes was much slower than random writes ------------------------------------------------------- This SF.Net email is sponsored by: IBM Linux Tutorials Free Linux tutorial presented by Daniel Robbins, President and CEO of GenToo technologies. Learn everything from fundamentals to system administration.http://ads.osdn.com/?ad_id=1470&alloc_id=3638&op=click _______________________________________________ NFS maillist - NFS@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/nfs