Return-Path: linux-nfs-owner@vger.kernel.org Received: from aserp1040.oracle.com ([141.146.126.69]:51122 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750850AbaJWNzm convert rfc822-to-8bit (ORCPT ); Thu, 23 Oct 2014 09:55:42 -0400 Content-Type: text/plain; charset=windows-1252 Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.6\)) Subject: Re: [PATCH v1 13/16] NFS: Add sidecar RPC client support From: Chuck Lever In-Reply-To: <20141023133229.GA16717@fieldses.org> Date: Thu, 23 Oct 2014 09:55:28 -0400 Cc: Trond Myklebust , Anna Schumaker , Linux NFS Mailing List , Tom Talpey Message-Id: References: <20141016192919.13414.3151.stgit@manet.1015granger.net> <20141016194000.13414.83844.stgit@manet.1015granger.net> <54454762.8020506@Netapp.com> <5BF0312C-06EC-4D83-81E9-F929724A0EAD@oracle.com> <20141023133229.GA16717@fieldses.org> To: "J. Bruce Fields" Sender: linux-nfs-owner@vger.kernel.org List-ID: On Oct 23, 2014, at 9:32 AM, J. Bruce Fields wrote: > On Tue, Oct 21, 2014 at 01:11:26PM -0400, Chuck Lever wrote: >> The size of the changeset _is_ the justification. It?s >> a much less invasive change to add a TCP side-car than >> it is to implement RDMA backchannel on both server and >> client. > > Something I'm confused about: is bidirectional RPC/RDMA optional or > mandatory for servers to implement? IMO bi-directional RPC/RDMA is not required anywhere in RFCs 5666 (the RPC/RDMA spec) or 5667 (the NFS on RPC/RDMA spec). > Something somewhere has to be mandatory if we want to guarantee a > working backchannel between any two implementations. -- Chuck Lever chuck[dot]lever[at]oracle[dot]com