From owner-freebsd-stable@FreeBSD.ORG Tue Apr 11 01:58:19 2006 Return-Path: X-Original-To: freebsd-stable@freebsd.org Delivered-To: freebsd-stable@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 2C4DB16A402 for ; Tue, 11 Apr 2006 01:58:19 +0000 (UTC) (envelope-from Mark_Andrews@isc.org) Received: from farside.isc.org (farside.isc.org [204.152.187.5]) by mx1.FreeBSD.org (Postfix) with ESMTP id 5563A43D53 for ; Tue, 11 Apr 2006 01:58:18 +0000 (GMT) (envelope-from Mark_Andrews@isc.org) Received: from drugs.dv.isc.org (localhost.isc.org [IPv6:::1]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by farside.isc.org (Postfix) with ESMTP id A7E11E611E for ; Tue, 11 Apr 2006 01:58:17 +0000 (UTC) (envelope-from marka@isc.org) Received: from drugs.dv.isc.org (localhost [127.0.0.1]) by drugs.dv.isc.org (8.13.4/8.13.4) with ESMTP id k3B1wC6R084032; Tue, 11 Apr 2006 11:58:12 +1000 (EST) (envelope-from marka@drugs.dv.isc.org) Message-Id: <200604110158.k3B1wC6R084032@drugs.dv.isc.org> To: Pete Slagle From: Mark Andrews In-reply-to: Your message of "Mon, 10 Apr 2006 18:45:53 MST." <443B0A51.8040206@voidcaptain.com> Date: Tue, 11 Apr 2006 11:58:12 +1000 Sender: Mark_Andrews@isc.org Cc: freebsd-stable@freebsd.org, michael.schuh@gmail.com, kris@obsecurity.org Subject: Re: Maximum Swapsize X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 11 Apr 2006 01:58:19 -0000 > Daniel O'Connor wrote: > > > The old "swap size = 2x RAM" rule is no longer applicable unless you have a > > > very special application. > > This "rule" always seemed counterintuitive to me anyway. > > When you have very limited physical RAM you need a lot of swap space. > When you have more than enough RAM you don't need any swap space at all. > For a given set of applications, as RAM increases you need less swap > space, not more. And vice versa. The rule was "a minimum of 2 time memory". This allowed to be able to swap between two processes consuming all of real memory. It dates backs to PDP 11 memory management models. Mark -- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: Mark_Andrews@isc.org