From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 3 Jul 2002 16:18:12 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 3 Jul 2002 16:18:11 -0400 Received: from mail.cafes.net ([207.65.182.3]:28651 "EHLO mail.cafes.net") by vger.kernel.org with ESMTP id ; Wed, 3 Jul 2002 16:18:10 -0400 To: linux-kernel@vger.kernel.org From: gphat@cafes.net Subject: Large numbers of TCP resets Date: Wed, 3 Jul 2002 20:15:53 GMT X-Originating-IP: 67.105.23.117 Message-Id: <20020703201553.DE9FD68CB5EA@mail.cafes.net> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Recently, the web-app at the company I work for started having problems load balancing. This was traced back to a large number of tcp-resets being sent from the web servers to the clients. Here's netstat output for one of the boxen: 437761 active connections openings 0 passive connection openings 21 failed connection attempts 0 connection resets received 101 connections established 140497907 segments received 149967684 segments send out 116610 segments retransmited 111 bad segments received. 1003306 resets sent This box is running an apache/tomcat/jboss setup serving both HTTP and RMI requests. The reset packets disrupt the load balancing method, as the load balancers think the reset means the connection can now be round-robined to the next machine. This can be masked by using cookie-based balancing, but I am worried that we would be masking a problem. Documentation concerning tuning buffers for network purposes say that 2.4 is good at auto-tuning, and that only /proc/sys/net/ipv4/tcp_wmem|tcp_rmem might need tweaking. The kernel is 2.4.9-31smp from RedHat 7.2. The cards are Intel 82557's. There are two interfaces, with 1 for client access and 1 used for communication with the backend database. (The ->client is the one we are worried about). Any ideas on why the interfaces would be doing this? The boxes served 1.6 hits/sec average over last month for a total of about 10Gb. Is there some tuning that needs to take place? Thanks in advance. Cory 'G' Watson