From owner-freebsd-questions@FreeBSD.ORG Mon Dec 24 23:06:23 2007 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id E234116A419 for ; Mon, 24 Dec 2007 23:06:23 +0000 (UTC) (envelope-from wundram@beenic.net) Received: from mail.beenic.net (mail.beenic.net [83.246.72.40]) by mx1.freebsd.org (Postfix) with ESMTP id A4BA513C457 for ; Mon, 24 Dec 2007 23:06:23 +0000 (UTC) (envelope-from wundram@beenic.net) Received: from phoenix (hnvr-4dbbb5d6.pool.einsundeins.de [77.187.181.214]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.beenic.net (Postfix) with ESMTP id 135D9A44529; Mon, 24 Dec 2007 23:58:49 +0100 (CET) From: "Heiko Wundram (Beenic)" Organization: Beenic Networks GmbH To: robert@webtent.com Date: Tue, 25 Dec 2007 01:06:18 +0100 User-Agent: KMail/1.9.7 References: <1198534892.11590.8.camel@columbus.webtent.org> In-Reply-To: <1198534892.11590.8.camel@columbus.webtent.org> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200712250106.19265.wundram@beenic.net> Cc: freebsd-questions@freebsd.org Subject: Re: 4GB memory and more 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: Mon, 24 Dec 2007 23:06:24 -0000 Am Montag, 24. Dezember 2007 23:21:32 schrieb Robert Fitzpatrick: > I have a couple of Supermicro servers and upgraded both with more > memory. I upgraded our ESMTP server from 1GB to 4GB and our MX server > from 2GB to 5GB. Below are the dmesg memory findings and, yes, I get the > memory over 4GB ignored when booting up. The ESMTP even says that about > 130MB is ignored. I was reading about building into the kernel PAE > options for using above 4GB of memory, but in the dmesg I see PAE in the > Features. Does this mean the support is there and I just need some BIOS > tweaking? Nope. This means that your CPU supports PAE, but says nothing about the operating system itself (whether it uses PAE or not). When you want a PAE-enabled kernel (i.e., one that uses PAE to see the "extra" memory), see the PAE kernel configuration in the sys/i386/conf directory of your sources tree, and build your own kernel with (for example, if you don't want to customize the kernel configuration): make kernconf=PAE buildworld buildkernel installkernel This builds a kernel which actually uses that interface to see the extra memory and allows you to access it in standard i386 mode. Generally, it's considered better practise to use the AMD64 architecture to access the high memory (because of performance considerations and driver compatability), but I don't know whether your CPUs actually support the x64 operating mode, so you may be stuck with using PAE. YMMV. -- Heiko Wundram Product & Application Development