Return-Path: linux-nfs-owner@vger.kernel.org Received: from mx2.netapp.com ([216.240.18.37]:37029 "EHLO mx2.netapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751507Ab1KJUnG convert rfc822-to-8bit (ORCPT ); Thu, 10 Nov 2011 15:43:06 -0500 Message-ID: <1320957784.11956.16.camel@lade.trondhjem.org> Subject: Re: unexpected NFS timeouts, related to sync/async soft mounts over TCP From: Trond Myklebust To: Andrew Cooper Cc: Chuck Lever , linux-nfs Date: Thu, 10 Nov 2011 15:43:04 -0500 In-Reply-To: <4EBBF35B.5000606@citrix.com> References: <4EBAC88D.40902@citrix.com> <4EBBB247.40805@citrix.com> <2E3D3F87-479E-4096-B086-C8F83A0147B5@oracle.com> <4EBBF35B.5000606@citrix.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Sender: linux-nfs-owner@vger.kernel.org List-ID: On Thu, 2011-11-10 at 15:52 +0000, Andrew Cooper wrote: > > On 10/11/11 15:29, Chuck Lever wrote: > > On Nov 10, 2011, at 6:15 AM, Andrew Cooper wrote: > > > >> On 09/11/11 22:36, Chuck Lever wrote: > >>> On Nov 9, 2011, at 1:38 PM, Andrew Cooper wrote: > Sorry. I am not sure I was clear. An EIO does not present itself with > a hard mount, but a TCP FIN is still injected into the stream by the > client, causing 15 seconds of deadlock, eventually fixed by sending a > RST and restarting with a new TCP stream. At this point, softmounts > throw an EIO while hardmounts restart and continue successfully. > > My problem is not the EIO on softmount or lack of EIO for hardmout, but > the fact that the client sees fit to try and close the TCP stream while > an apparently otherwise healthy NFS session is ongoing. The client will attempt to close the TCP connection on any RPC level error. That can happen, e.g., if the server sends a faulty RPC/TCP record fragment header or some other garbage data. I'm assuming that you've checked that the TCP parameters are set to sane values for a 10GigE connection (i.e. tcp_timestamps is on) so that there is no corruption happening at that level? Cheers Trond -- Trond Myklebust Linux NFS client maintainer NetApp Trond.Myklebust@netapp.com www.netapp.com