From owner-freebsd-fs@FreeBSD.ORG Fri Oct 14 16:18:15 2005 Return-Path: X-Original-To: fs@freebsd.org Delivered-To: freebsd-fs@FreeBSD.ORG Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 3D91916A41F for ; Fri, 14 Oct 2005 16:18:15 +0000 (GMT) (envelope-from anderson@centtech.com) Received: from mh1.centtech.com (moat3.centtech.com [207.200.51.50]) by mx1.FreeBSD.org (Postfix) with ESMTP id CC85C43D45 for ; Fri, 14 Oct 2005 16:18:14 +0000 (GMT) (envelope-from anderson@centtech.com) Received: from [10.177.171.220] (neutrino.centtech.com [10.177.171.220]) by mh1.centtech.com (8.13.1/8.13.1) with ESMTP id j9EGIDYH009732; Fri, 14 Oct 2005 11:18:14 -0500 (CDT) (envelope-from anderson@centtech.com) Message-ID: <434FDA30.1040204@centtech.com> Date: Fri, 14 Oct 2005 11:17:52 -0500 From: Eric Anderson User-Agent: Mozilla/5.0 (X11; U; FreeBSD i386; en-US; rv:1.7.11) Gecko/20050914 X-Accept-Language: en-us, en MIME-Version: 1.0 To: rick@snowhite.cis.uoguelph.ca References: <200510141607.MAA21757@snowhite.cis.uoguelph.ca> In-Reply-To: <200510141607.MAA21757@snowhite.cis.uoguelph.ca> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: ClamAV 0.82/1134/Fri Oct 14 03:07:44 2005 on mh1.centtech.com X-Virus-Status: Clean Cc: fs@freebsd.org Subject: Re: FreeBSD NFS server not responding to TCP SYN packets from Linux/SunOS clients 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, 14 Oct 2005 16:18:15 -0000 rick@snowhite.cis.uoguelph.ca wrote: [..snip..] > rick > ps: It would be nice if someone with the right expertise could explore > other things in TCP specifically for NFS. For example, I don't see > why a retransmit timeout should go above about 100msec, since net > delays are well below that level, even half way around the world > these days. Having said that, I don't know enough about TCP retransmit > to say that one second retry intervals aren't correct? Wouldn't this be a problem for a server under high disk load? If the disks are very very busy, and clients are requesting stat's on files, etc, then the server would be waiting on disk, and the time could be way more than 100ms, even more than 1s. Of course, this would be a slow server because of the load, however it does occur, and so lowering it to 100msec might be too aggresive. If you have many many clients, all attempting lots of NFS activity, during times of load you could make the server even more overloaded with all the retransmits, right? Eric -- ------------------------------------------------------------------------ Eric Anderson Sr. Systems Administrator Centaur Technology Anything that works is better than anything that doesn't. ------------------------------------------------------------------------