From owner-freebsd-isp@FreeBSD.ORG Wed Dec 10 06:41:17 2003 Return-Path: Delivered-To: freebsd-isp@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 2669716A4CE; Wed, 10 Dec 2003 06:41:17 -0800 (PST) Received: from bilver.wjv.com (user38.net339.fl.sprint-hsd.net [65.40.24.38]) by mx1.FreeBSD.org (Postfix) with ESMTP id 9896F43D13; Wed, 10 Dec 2003 06:41:15 -0800 (PST) (envelope-from bv@bilver.wjv.com) Received: from bilver.wjv.com (localhost.wjv.com [127.0.0.1]) by bilver.wjv.com (8.12.10/8.12.10) with ESMTP id hBAEfCm7096002; Wed, 10 Dec 2003 09:41:12 -0500 (EST) (envelope-from bv@bilver.wjv.com) Received: (from bv@localhost) by bilver.wjv.com (8.12.10/8.12.10/Submit) id hBAEfBWR096001; Wed, 10 Dec 2003 09:41:11 -0500 (EST) (envelope-from bv) Date: Wed, 10 Dec 2003 09:41:11 -0500 From: Bill Vermillion To: freebsd-isp@freebds.org Message-ID: <20031210144111.GC95844@wjv.com> References: <20571.148.243.211.1.1071036438.squirrel@mail.unixmexico.com> <20031210023427.T14579@odysseus.silby.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20031210023427.T14579@odysseus.silby.com> Organization: W.J.Vermillion / Orlando - Winter Park ReplyTo: bv@wjv.com User-Agent: Mutt/1.5.5.1i X-Spam-Status: No, hits=0.0 required=5.0 tests=none autolearn=no version=2.60 X-Spam-Checker-Version: SpamAssassin 2.60 (1.212-2003-09-23-exp) on bilver.wjv.com cc: nbari@unixmexico.com cc: freebsd-isp@freebsd.org cc: freebsd-hackers@freebsd.org Subject: Re: adding more ram X-BeenThere: freebsd-isp@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list Reply-To: bv@wjv.com List-Id: Internet Services Providers List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 10 Dec 2003 14:41:17 -0000 While normally not able to pour water out of a boot with instructions on the heel, on Wed, Dec 10, 2003 at 02:41 our dear friend Mike Silbersack uttered this load of codswallop: Just one slight addendum here. > I'm replying because I want to answer your real question. > The notion of swap = 2 x ram is an old one, and is no > longer applicable. (Some) older VM systems used very simplistic > swapping mechanisms, which required entire processes to be > swapped, thereby requiring large amounts of swap space. FreeBSD > (and other modern OSes) page out to the swap file in increments > of 4K pages, and do so in a flexible manner. As a result, you > should always have *some* swap space to handle overload cases, > but it's not necessary to keep any specific ram to swap ratio. Systems such as the Irix I used before moving the servers to FBSD around 1996 - reserverd swap space for applications when the application started up so those needed large swap space. Often it was never used, but the design allocated it anyway. Bill -- Bill Vermillion - bv @ wjv . com