Return-Path: Received: from acsinet11.oracle.com ([141.146.126.233]:19518 "EHLO acsinet11.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754043Ab0AYQt0 (ORCPT ); Mon, 25 Jan 2010 11:49:26 -0500 Cc: "Muntz, Daniel" , Peter Chacko , linux-nfs@vger.kernel.org Message-Id: <0BA6F612-CE3A-47E9-B436-57E48506D769@oracle.com> From: Chuck Lever To: Whoop Whouzer In-Reply-To: Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Subject: Re: nfs client performance while server is down Date: Mon, 25 Jan 2010 11:48:59 -0500 References: <1f808b4a1001230757i2027d32dxb48482ea7bf8e4ee@mail.gmail.com> <7A24DF798E223B4C9864E8F92E8C93EC0527810C@SACMVEXC1-PRD.hq.netapp.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: MIME-Version: 1.0 On Jan 24, 2010, at 7:09 PM, Whoop Whouzer wrote: > I did some network traces and there is nothing strange happening as > far as I can tell. I shut down the server (some network traffic > occurred as is to be expected). It got quiet again, I launched > nautilus, it got stuck without displaying anything and there was no > real network activity except 3 broadcasts using the ARP protocol > asking where the server was (could be just coincidence). That sounds like the client does want to reconnect with the server. You could try enabling debug tracing on your client (sudo rpcdebug -m nfs -s all) after shutting down your server, then try to start nautilus. The kernel log would then contain NFS-related messages that might indicate where to look next. > Closing > nautilus and launching it again will let it hang again but I see no > additional network traffic. After a while nautilus will display the > contents of the folder without any network traffic. > > On Sun, Jan 24, 2010 at 10:34 PM, Muntz, Daniel > wrote: >> Perhaps something in your $PATH is in the NFS mount? Do a network >> trace and maybe you can see if, in fact, there are actually NFS >> operations being attempted that you weren't expecting. Then try to >> figure out why. >> >> -Dan >> >>> -----Original Message----- >>> From: Whoop Whouzer [mailto:tiredandnumb@gmail.com] >>> Sent: Saturday, January 23, 2010 8:28 AM >>> To: Peter Chacko >>> Cc: linux-nfs@vger.kernel.org >>> Subject: Re: nfs client performance while server is down >>> >>> I don't remember all the different set-ups I tried it on, but I just >>> confirmed this with the following combinations: >>> >>> ubuntu server 10.04 (alpha 2) --> ubuntu desktop 9.10, ubuntu >>> desktop >>> 10.04 (alpha 2), fedora 12 >>> ubuntu server 9.10 --> ubuntu desktop 9.10, ubuntu desktop 10.04 >>> (alpha 2), fedora 12 >>> >>> I'll be happy to test it on another client machine (distro) even >>> another server (although it would require a little more time) >>> >>> Here are some examples on the bugreports I noticed and how they do >>> not >>> seem to get solved: >>> https://bugzilla.redhat.com/show_bug.cgi?id=175283 >>> https://bugs.launchpad.net/ubuntu/+source/nfs-utils/+bug/164120 >>> >>> regards, >>> Whoop >>> >>> On Sat, Jan 23, 2010 at 4:57 PM, Peter Chacko >>> wrote: >>>> Which client OS you observed this behavior ? This has nothing to >>>> do >>>> NFS design, and its purely stateless...Its upto the client OS >>>> implementation about aspects like how to deal with local >>> IO, when NFS >>>> share gets disconnected.. >>>> >>>> May be a VFS bug on the local OS you found this problem .. >>>> >>>> thanks >>>> >>>> On Sat, Jan 23, 2010 at 9:15 PM, Whoop Whouzer >>> wrote: >>>>> Howdy, >>>>> >>>>> I was wondering why nfs is designed in such a way that the >>> performance >>>>> of an nfs client machine gets very bad when the nfs server >>> is offline? >>>>> This is even the case with a soft mount (either via mount >>> or fstab). >>>>> Just about every application that requires disk access (not >>>>> talking >>>>> about nfs share acces) gets really slow to unresponsive. >>> For instance >>>>> nautilus becomes unresponsive when displaying the contents of any >>>>> folder on the local disk, >>>>> playing movie files (stored on local disk) let totem or >>> vlc get stuck >>>>> on set intervals, even the terminal becomes unresponsive at times. >>>>> >>>>> I could understand that these problems would occur while >>> accessing the >>>>> nfs share directoiourry while the server is offline, but >>> why for totally >>>>> unrelated directories? >>>>> >>>>> I have experienced this behaviour on various distro's, and >>> also found >>>>> various bug reports on this issue, they don't seem to get solved >>>>> as >>>>> this is viewed as nfs design. >>>>> I see this as a flaw because clients are totally dependent on the >>>>> server. This would be less of a deal if the entire home directory >>>>> would be stored on nfs (although I even think some sort of >>>>> synchronisation technology could and should be implemented in this >>>>> case). It is a bit odd that (technically) one machine serving some >>>>> "useless" files to a non-trivial directory on client >>> machines can take >>>>> down these client machines. >>>>> >>>>> For me the preferred functionality would be: >>>>> *If an nfs server gets offline the client's nfs share becomes >>>>> unaccessible, but local directories and applications (that only >>>>> require local disk access) stay responsive. >>>>> *If an nfs server gets online (after being offline while the >>>>> client >>>>> has not been restarted) the nfs share becomes reconnected. >>>>> >>>>> regards, >>>>> Whoop >>>>> -- >>>>> To unsubscribe from this list: send the line "unsubscribe >>> linux-nfs" in >>>>> the body of a message to majordomo@vger.kernel.org >>>>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>>>> >>>> >>> -- >>> To unsubscribe from this list: send the line "unsubscribe >>> linux-nfs" in >>> the body of a message to majordomo@vger.kernel.org >>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>> >> > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" > in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Chuck Lever chuck[dot]lever[at]oracle[dot]com