From owner-freebsd-questions@FreeBSD.ORG Wed Jan 16 16:28:08 2008 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 1D67016A420 for ; Wed, 16 Jan 2008 16:28:08 +0000 (UTC) (envelope-from dan@dan.emsphone.com) Received: from dan.emsphone.com (dan.emsphone.com [199.67.51.101]) by mx1.freebsd.org (Postfix) with ESMTP id D941113C455 for ; Wed, 16 Jan 2008 16:28:07 +0000 (UTC) (envelope-from dan@dan.emsphone.com) Received: (from dan@localhost) by dan.emsphone.com (8.14.2/8.14.2) id m0GGS6it028317; Wed, 16 Jan 2008 10:28:06 -0600 (CST) (envelope-from dan) Date: Wed, 16 Jan 2008 10:28:06 -0600 From: Dan Nelson To: Albert Shih Message-ID: <20080116162805.GH97708@dan.emsphone.com> References: <20080116150454.GP89314@pcjas.obspm.fr> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080116150454.GP89314@pcjas.obspm.fr> X-OS: FreeBSD 7.0-PRERELEASE User-Agent: Mutt/1.5.17 (2007-11-01) Cc: freebsd-questions@freebsd.org Subject: Re: How manu swap ? 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, 16 Jan 2008 16:28:08 -0000 In the last episode (Jan 16), Albert Shih said: > Hi all > > I known it's classic question. > > Long time ago when I install a FreeBSD x86 32 bits when I have N Go > of Ram the installer take 2xN Go for the swap partition. > > Now I just install two machine with FreeBSD amd64 version with 8Go of > Ram and FreeBSD installer take 4 Go of swap. > > Is a bug in the installer or now FreeBSD don't need 2xRam of swap ? When was the last time you saw your swap partition with more than 2GB in use? On an 8GB system, you probably will either never have enough processes to require swapping at all, or you will have one or two processes so big that if they ever swap, it's a sign you need more RAM, not more swap :) In systems with that much RAM, swap is pretty much only used for crashdumps, and with minidumps enabled by default, you don't need much. On small systems, the 2x-swap rule was because once you allocated enough processes to require that much swap, you were pretty much thrashing your system anyway. -- Dan Nelson dnelson@allantgroup.com