From owner-freebsd-performance@FreeBSD.ORG Wed Aug 11 17:39:17 2010 Return-Path: Delivered-To: freebsd-performance@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id CFB9D1065674 for ; Wed, 11 Aug 2010 17:39:17 +0000 (UTC) (envelope-from markham_breitbach@ssimicro.com) Received: from mail.ssimicro.com (mail.ssimicro.com [64.247.129.10]) by mx1.freebsd.org (Postfix) with ESMTP id 9FAF38FC17 for ; Wed, 11 Aug 2010 17:39:17 +0000 (UTC) Received: from beaver.ssimicro.com (beaver.ssimicro.com [199.247.84.12]) (authenticated bits=0) by mail.ssimicro.com (8.14.4/8.14.4) with ESMTP id o7BH09vK089100 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NOT) for ; Wed, 11 Aug 2010 11:00:09 -0600 (MDT) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.96.1 at mail.ssimicro.com Message-ID: <4C62D827.2030409@ssimicro.com> Date: Wed, 11 Aug 2010 11:04:39 -0600 From: markham breitbach User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:1.9.2.8) Gecko/20100802 Thunderbird/3.1.2 MIME-Version: 1.0 To: freebsd-performance@freebsd.org X-Enigmail-Version: 1.1.1 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: massive load average spikes X-BeenThere: freebsd-performance@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Performance/tuning List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 11 Aug 2010 17:39:17 -0000 Good Day, I am running into an issue where I am seeing load average on a server suddenly jump from nominal values around 0.5 to anywhere from 10 up over 70 in under 1 second. This does not seem to be related to CPU overload, and LA immediately begins to fall back again to nominal. This does not seem to happen with any regular frequency, and can happen several times an hour or not for hours. I am running 6.4-RELEASE-p8 with the SMP kernel and interrupt polling enabled. (I have also tried without either) The server is running a mail server in a jail (sendmail, dovecot, etc) with the jail being a full "build world" and servicing about 2000 users for SMTP, POP3 and IMAP. The hardware is a Silicon Mechanics (Super Micro) dual 4core Xeon (E5405) with 4GB RAM and multiple 7200 RPM sata. I have tried watching top, vmstat, iostat and systat to see if I can correlate something to these spikes in load average, but nothing really stands out. Can anyone suggest what may be causing this or how to track that down? Many Thanks, Markham Breitbach SSi Network Operations