From owner-freebsd-questions@FreeBSD.ORG Wed Dec 28 03:29:27 2005 Return-Path: X-Original-To: freebsd-questions@freebsd.org Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 2B90916A422 for ; Wed, 28 Dec 2005 03:29:27 +0000 (GMT) (envelope-from cswiger@mac.com) Received: from pi.codefab.com (pi.codefab.com [199.103.21.227]) by mx1.FreeBSD.org (Postfix) with ESMTP id F0BB243D5E for ; Wed, 28 Dec 2005 03:29:22 +0000 (GMT) (envelope-from cswiger@mac.com) Received: from localhost (localhost [127.0.0.1]) by pi.codefab.com (Postfix) with ESMTP id 2C5155D78; Tue, 27 Dec 2005 22:29:22 -0500 (EST) Received: from pi.codefab.com ([127.0.0.1]) by localhost (pi.codefab.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 33218-10; Tue, 27 Dec 2005 22:29:20 -0500 (EST) Received: from [192.168.1.3] (pool-68-161-122-227.ny325.east.verizon.net [68.161.122.227]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by pi.codefab.com (Postfix) with ESMTP id 7E4F75C80; Tue, 27 Dec 2005 22:29:19 -0500 (EST) Message-ID: <43B2069B.2000302@mac.com> Date: Tue, 27 Dec 2005 22:29:31 -0500 From: Chuck Swiger Organization: The Courts of Chaos User-Agent: Mozilla Thunderbird 1.0.7 (Windows/20050923) X-Accept-Language: en-us, en MIME-Version: 1.0 To: "Marc G. Fournier" References: <20051227211433.J1087@ganymede.hub.org> In-Reply-To: <20051227211433.J1087@ganymede.hub.org> X-Enigmail-Version: 0.93.0.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: amavisd-new at codefab.com Cc: freebsd-questions@freebsd.org Subject: Re: "Load Balancing": How Busy are the servers? X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 28 Dec 2005 03:29:27 -0000 Marc G. Fournier wrote: > 1. What variables on a server should be monitored to determine how busy > a server is? For instance, I've always been taugth that 'loadavg' is > not an indication of how busy a server is, since a high loadavg on a > single CPU server might be an overloaded server, but moderately loaded > on a dual CPU server ... If the load average is greater than the number of CPU's, it's likely that adding another CPU would improve throughput. If the load average is more than twice the # of CPU's it's extremely likeing that adding more CPUs would improve throughput. > disk i/o, cpu usage, ethernet throughput ... what else? The primary resources are CPU, memory, and I/O. If you measure the ones you've listed and pay attention to the VM stats, you should have a starting point. Don't forget to pay attention to running out of disk space, SysV shmem semaphores, and anything else which is being used by the tasks being run. > 2. Are there any tools that I can run to give me a point in time > "summary" of how busy a server is based on these several factors? "vmstat 5" and "iostat 5" come pretty close, but you have to calibrate some of the I/O measurements it returns against the maximum throughput possible for each specific system. > Basically, I'd like to keep track of multiple servers and be able to say > "this server is running >75% of capacity, time to upgrade or move things > off of it" ... if its possible ... ? Take a look at Big Brother, www.bb4.org?, it will at least give warnings for high load average, disk space, and so forth. -- -Chuck