Return-Path: linux-nfs-owner@vger.kernel.org Received: from fieldses.org ([174.143.236.118]:47352 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755701Ab3IKUOk (ORCPT ); Wed, 11 Sep 2013 16:14:40 -0400 Date: Wed, 11 Sep 2013 16:14:39 -0400 To: Emmanuel Florac Cc: linux-nfs@vger.kernel.org Subject: Re: Hard to debug NFS loss of connectivity: problem solved Message-ID: <20130911201439.GA1462@fieldses.org> References: <20130905191800.1c75b2fb@harpe.intellique.com> <20130911171145.323f9b9e@harpe.intellique.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 In-Reply-To: <20130911171145.323f9b9e@harpe.intellique.com> From: "J. Bruce Fields" Sender: linux-nfs-owner@vger.kernel.org List-ID: On Wed, Sep 11, 2013 at 05:11:45PM +0200, Emmanuel Florac wrote: > Le Thu, 5 Sep 2013 19:18:00 +0200 > Emmanuel Florac écrivait: > > > Any hint, idea, etc would be extremely welcome. Even some > > debugging method less painful than digging through huge > > tcpdumps would be nice :) > > I post this answer in the faint hope that it may avoid a long and > painful week of testing to someone else :) > > The problem comes from the virtual network adapter "Intel pro 1000" > using the e1000e linux driver. The Intel hardware supports a MTU of > 4078 max. On a physical machine, it will fail to set up a greater value > with something like: > > # ifconfig eth0 mtu 4079 > SIOCSIFMTU: Invalid argument > > However the virtual e1000 from VMWare ESX silently accept any value; > then it will mostly work, and fail in mysterious way and only with > certain protocols (such as nfs). Ah-hah! Thanks for the followup.--b. > > In the case of VMWare virtual machines, using a vmnet3 virtual network > adapter works fine with a mtu of 9000 under NFS. Therefore the problem > is solved. > > For the sake of completeness and curiosity, I'll try and see what > happens with a KVM e1000 virtual device. > > -- > ------------------------------------------------------------------------ > Emmanuel Florac | Direction technique > | Intellique > | > | +33 1 78 94 84 02 > ------------------------------------------------------------------------ > -- > 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