From owner-freebsd-fs@FreeBSD.ORG Fri Aug 10 17:30:48 2007 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id A9D9C16A41A for ; Fri, 10 Aug 2007 17:30:48 +0000 (UTC) (envelope-from scottl@samsco.org) Received: from pooker.samsco.org (pooker.samsco.org [168.103.85.57]) by mx1.freebsd.org (Postfix) with ESMTP id 4C41D13C4A5 for ; Fri, 10 Aug 2007 17:30:48 +0000 (UTC) (envelope-from scottl@samsco.org) Received: from phobos.samsco.home (phobos.samsco.home [192.168.254.11]) (authenticated bits=0) by pooker.samsco.org (8.13.8/8.13.8) with ESMTP id l7AGwoRh057242; Fri, 10 Aug 2007 10:58:51 -0600 (MDT) (envelope-from scottl@samsco.org) Message-ID: <46BC9944.9010408@samsco.org> Date: Fri, 10 Aug 2007 10:58:44 -0600 From: Scott Long User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X; en-US; rv:1.8.1.6) Gecko/20070802 SeaMonkey/1.1.4 MIME-Version: 1.0 To: Rick Macklem References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH authentication, not delayed by milter-greylist-2.0.2 (pooker.samsco.org [168.103.85.57]); Fri, 10 Aug 2007 10:58:51 -0600 (MDT) X-Spam-Status: No, score=-1.4 required=5.5 tests=ALL_TRUSTED autolearn=failed version=3.1.8 X-Spam-Checker-Version: SpamAssassin 3.1.8 (2007-02-13) on pooker.samsco.org Cc: freebsd-fs@freebsd.org Subject: Re: multiplexing TCP sockets in the NFS client X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 10 Aug 2007 17:30:48 -0000 Rick Macklem wrote: > Long long ago, I felt it might be better to use a separate TCP socket > for each mount to the same server. The argument was along the lines of: > > Some mounts might be much busier than others and, as such, the > separate TCP socket would provide feedback to the client w.r.t. > load on that mount. The assumption w.r.t. busier mount points > tacitly assumed separate disks with some disks experiencing > heavy I/O loads. > > It seems to me that these days, what with SANs, RAIDs, GEOM,... that a > mount point probably isn't going to reflect a different disk subsystem > so much as an administrative boundary. Also, it's not obvious that the > feedback argument is relevant anyhow, since clients will still receive > replies when the server gets around to doing the RPC, in any case. > > So, I'm thinking that it might be better to change the client code so that > it shares one TCP connection between all mounts to the same server. This > reduces the number of TCP connections (possibly an issue if clients use > an automounter to do a lot of mounts). It might also help w.r.t transport > performance by increasing the volume of data being transferred on the TCP > connection? (I don't know enough about current TCP stacks to know if this > is the case or not?) > > Any comments? rick > Is SCTP of any interest in the NFS world? Scott