From owner-freebsd-performance@FreeBSD.ORG Wed Apr 30 18:45:12 2003 Return-Path: Delivered-To: freebsd-performance@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 1285637B404 for ; Wed, 30 Apr 2003 18:45:12 -0700 (PDT) Received: from sabre.velocet.net (sabre.velocet.net [216.138.209.205]) by mx1.FreeBSD.org (Postfix) with ESMTP id F3C0743FCB for ; Wed, 30 Apr 2003 18:45:09 -0700 (PDT) (envelope-from dgilbert@velocet.ca) Received: from trooper.velocet.ca (trooper.velocet.net [216.138.242.2]) by sabre.velocet.net (Postfix) with ESMTP id E920C13824A; Wed, 30 Apr 2003 21:45:07 -0400 (EDT) Received: by trooper.velocet.ca (Postfix, from userid 66) id 992817478C; Wed, 30 Apr 2003 21:45:07 -0400 (EDT) Received: by canoe.velocet.net (Postfix, from userid 101) id AC3CF567609; Wed, 30 Apr 2003 21:45:03 -0400 (EDT) From: David Gilbert MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <16048.31775.642709.140262@canoe.velocet.net> Date: Wed, 30 Apr 2003 21:45:03 -0400 To: "Jin Guojun [DSD]" In-Reply-To: <3EB05582.297F50AE@lbl.gov> References: <200304281054.48976.ryba@kompakt.pl> <20030430174616.E59039@lorax.ubergeeks.com> <3EB05582.297F50AE@lbl.gov> X-Mailer: VM 7.07 under 21.1 (patch 14) "Cuyahoga Valley" XEmacs Lucid cc: Adrian Filipi-Martin cc: freebsd-performance@freebsd.org cc: Michael Nottebrock Subject: Re: SWAP size X-BeenThere: freebsd-performance@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Performance/tuning List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 01 May 2003 01:45:12 -0000 >>>>> "Jin" == Jin Guojun <[DSD]" > writes: Jin> not have a lot of RAM, though ...") if (1) no money to buy more Jin> RAM, (2) no slot to put more RAM or (3) it is a server just favor Jin> by every user to run their programs. Jin> Swap space is prepared for too many processes outrunning the RAM. Jin> It is not for improving performance, but exchange cost of disk Jin> for RAM. More swap space required means that more swap time Jin> means slow. Another thing working in favour of 2x swap is that disk has been becoming that much cheaper. With 1G and 2G disks, I was carefully considering the 256M of swap (2x 128M of memory) that I configured. With disks of 80G and more, I have been putting 1G of swap on every spindle I install because it really doesn't make a difference and I'd rather have 4x 1G swap partitions spread across spindles than only one 4G partition. That's not to claim that I have 2G of RAM (I actually have 1G), but disk space in general has become amazingly cheap. Dave. -- ============================================================================ |David Gilbert, Velocet Communications. | Two things can only be | |Mail: dgilbert@velocet.net | equal if and only if they | |http://daveg.ca | are precisely opposite. | =========================================================GLO================