From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 25976 invoked by alias); 6 Feb 2009 00:02:36 -0000 Received: (qmail 25797 invoked by uid 22791); 6 Feb 2009 00:02:34 -0000 X-SWARE-Spam-Status: No, hits=-2.6 required=5.0 tests=BAYES_00 X-Spam-Check-By: sourceware.org Received: from web65412.mail.ac4.yahoo.com (HELO web65412.mail.ac4.yahoo.com) (76.13.9.32) by sourceware.org (qpsmtpd/0.43rc1) with SMTP; Fri, 06 Feb 2009 00:02:30 +0000 Received: (qmail 98715 invoked by uid 60001); 6 Feb 2009 00:02:27 -0000 Message-ID: <810999.94407.qm@web65412.mail.ac4.yahoo.com> Received: from [206.223.182.162] by web65412.mail.ac4.yahoo.com via HTTP; Thu, 05 Feb 2009 16:02:27 PST Date: Fri, 06 Feb 2009 00:29:00 -0000 From: Andrew Klaassen Reply-To: clawsoon@yahoo.com Subject: Systemtap to predict memory upgrade needs To: systemtap@sources.redhat.com MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-IsSubscribed: yes Mailing-List: contact systemtap-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: systemtap-owner@sourceware.org X-SW-Source: 2009-q1/txt/msg00374.txt.bz2 Hi. I'm brand new to systemtap. I'm trying to write a script that'll monitor a currently running fileserver and tell me how often the physical disk will get hit if I double/quadruple/etc my RAM. Here's what I've figured out so far: I need to hook into all possible read/write operations (aio_read/write, regular read/write, readv/writev, sendfile, etc). My script then needs to duplicate the kernel buffer/paging logic, substituting my desired memory size for my actual memory size. This seems really complicated. (I am a lowly sysadmin, so I'm way over my head here.) Is there a simpler way? Is this something someone has already built? Thanks. Andrew