From owner-freebsd-questions@FreeBSD.ORG Wed Jan 16 16:55:30 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 EA26D16A41A for ; Wed, 16 Jan 2008 16:55:30 +0000 (UTC) (envelope-from jerrymc@gizmo.acns.msu.edu) Received: from gizmo.acns.msu.edu (gizmo.acns.msu.edu [35.8.1.43]) by mx1.freebsd.org (Postfix) with ESMTP id A1F5C13C458 for ; Wed, 16 Jan 2008 16:55:30 +0000 (UTC) (envelope-from jerrymc@gizmo.acns.msu.edu) Received: from gizmo.acns.msu.edu (localhost [127.0.0.1]) by gizmo.acns.msu.edu (8.13.6/8.13.6) with ESMTP id m0GGrCmi087770; Wed, 16 Jan 2008 11:53:12 -0500 (EST) (envelope-from jerrymc@gizmo.acns.msu.edu) Received: (from jerrymc@localhost) by gizmo.acns.msu.edu (8.13.6/8.13.6/Submit) id m0GGrCWV087769; Wed, 16 Jan 2008 11:53:12 -0500 (EST) (envelope-from jerrymc) Date: Wed, 16 Jan 2008 11:53:12 -0500 From: Jerry McAllister To: Dan Nelson Message-ID: <20080116165312.GC87571@gizmo.acns.msu.edu> References: <20080116150454.GP89314@pcjas.obspm.fr> <20080116162805.GH97708@dan.emsphone.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080116162805.GH97708@dan.emsphone.com> User-Agent: Mutt/1.4.2.2i Cc: Albert Shih , 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 16:55:31 -0000 On Wed, Jan 16, 2008 at 10:28:06AM -0600, Dan Nelson wrote: > 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. Don't forget that the system uses swap space to do paging too and that frequently used processes can end up in swap and be run from there faster than from regular disk. But, yes, the 2X rule was generally a combination of space for crash-dump plus room to run more than memory can hold. ////jerry > > -- > Dan Nelson > dnelson@allantgroup.com > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to "freebsd-questions-unsubscribe@freebsd.org"