From owner-freebsd-current@FreeBSD.ORG Fri Jan 9 02:28:06 2004 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 41ACC16A4CE for ; Fri, 9 Jan 2004 02:28:06 -0800 (PST) Received: from mailtoaster1.pipeline.ch (mailtoaster1.pipeline.ch [62.48.0.70]) by mx1.FreeBSD.org (Postfix) with ESMTP id 7BA0043D46 for ; Fri, 9 Jan 2004 02:28:03 -0800 (PST) (envelope-from andre@freebsd.org) Received: (qmail 57942 invoked from network); 9 Jan 2004 10:28:02 -0000 Received: from unknown (HELO freebsd.org) ([62.48.0.53]) (envelope-sender ) by mailtoaster1.pipeline.ch (qmail-ldap-1.03) with SMTP for ; 9 Jan 2004 10:28:02 -0000 Message-ID: <3FFE8232.730F70B8@freebsd.org> Date: Fri, 09 Jan 2004 11:28:02 +0100 From: Andre Oppermann X-Mailer: Mozilla 4.76 [en] (Windows NT 5.0; U) X-Accept-Language: en MIME-Version: 1.0 To: Thorsten Greiner References: <20040109085522.GB4246@tybalt.nev.psi.de> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit cc: current@FreeBSD.org Subject: Re: the TCP MSS resource exhaustion commit X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 09 Jan 2004 10:28:06 -0000 Thorsten Greiner wrote: > > Hi, > > I have some problems after this commit. The scenario is the > following: > > I have a JBoss Application Server running on the FreeBSD 5.2-CURRENT > machine which connects to an Oracle database (on a Sun). On several > occasions the connection to the database is forcefully closed and I > see the following messages in /var/log/messages: > > Jan 9 09:39:29 tybalt kernel: too many small tcp packets from > XX.XX.XX.XX:61701, av. 108byte/packet, dropping connection > Jan 9 09:39:35 tybalt kernel: too many small tcp packets from > XX.XX.XX.XX:61701, av. 108byte/packet, dropping connection > Jan 9 09:45:44 tybalt kernel: too many small tcp packets from > XX.XX.XX.XX:61701, av. 109byte/packet, dropping connection > > Is there any w/around? What are the proper settings for > net.inet.tcp.minmss and net.inet.tcp.minmssoverload in my scenario? You can simply increase net.inet.tcp.minmssoverload to any higher value. I suggest 2,000 as next step. If set it to 0 the check will be disabled entirely. This makes we wonder why the Oracle database server is sending so many small packets. Is your JBoss application doing connection pooling (eg. multiplexing multiple SQL sessions over one tcp session)? The documentation for these sysctl's is on its way. -- Andre > Regards > > -Thorsten > > -- > Williams and Holland's Law: > If enough data is collected, anything may be proven by > statistical methods. > > -------------------------------------------------------------------------------- > Part 1.2Type: application/pgp-signature