From owner-freebsd-questions Thu Nov 21 16: 5:15 2002 Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 767CF37B401 for ; Thu, 21 Nov 2002 16:05:14 -0800 (PST) Received: from smtp.infracaninophile.co.uk (happy-idiot-talk.infracaninophile.co.uk [81.2.69.218]) by mx1.FreeBSD.org (Postfix) with ESMTP id E2E0843E3B for ; Thu, 21 Nov 2002 16:05:12 -0800 (PST) (envelope-from m.seaman@infracaninophile.co.uk) Received: from happy-idiot-talk.infracaninophile.co.uk (localhost [IPv6:::1]) by smtp.infracaninophile.co.uk (8.12.6/8.12.6) with ESMTP id gAM053x2023292 for ; Fri, 22 Nov 2002 00:05:03 GMT (envelope-from matthew@happy-idiot-talk.infracaninophile.co.uk) Received: (from matthew@localhost) by happy-idiot-talk.infracaninophile.co.uk (8.12.6/8.12.6/Submit) id gAM04wGk023287 for questions@FreeBSD.ORG; Fri, 22 Nov 2002 00:04:58 GMT Date: Fri, 22 Nov 2002 00:04:58 +0000 From: Matthew Seaman To: FreeBSD List Subject: Re: A question of where to put swap Message-ID: <20021122000458.GA79549@happy-idiot-talk.infracaninophi> Mail-Followup-To: Matthew Seaman , FreeBSD List References: <20021121234453.GA62470@raggedclown.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20021121234453.GA62470@raggedclown.net> User-Agent: Mutt/1.5.1i X-Spam-Status: No, hits=-2.7 required=5.0 tests=IN_REP_TO,QUOTED_EMAIL_TEXT,REFERENCES,SPAM_PHRASE_03_05, USER_AGENT,USER_AGENT_MUTT version=2.43 Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On Fri, Nov 22, 2002 at 12:44:54AM +0100, Cliff Sarginson wrote: > I am in the business of re-arranging my disk layouts to reflect the > realities if life :) > My FreeBSD system currently runs on a SCSI-3 Disk, but I have two > modern, fast IDE disks that will be gaining a considerable amount of > free space in the re-arrangements. I tend to run during the course of > the day several extremely memory loving programs which cause > paging/swapping to occur. I would like opinions on whether I would > notice an improvement if I moved the swap area (which lives on the SCSI > disk with the rest of the system) to the front of one of the IDE disks. > I intend to make a new slice on the IDE disk anyway. A good thing to do is to put a swap partition on each disk[*]. That permits the system to maximize IO throughput while paging. You can divide up your total required swap space between the three disks however you want, but remember that to be able to get a system crash dump, you need at least one of your swap areas to be slightly larger than the amount of RAM in your machine. Having approximately equally sized swap areas gets the absolute maximum performance out of the machine --- see The Handbook, Section 6.2.1.2 http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/configtuning-initial.html Cheers, Matthew [*] so long as the IDE drives are on different channels --- you won't gain anything by having swap areas (or any areas of high disk IO for that matter) on both Master and Slave on the same channel. -- Dr Matthew J Seaman MA, D.Phil. 26 The Paddocks Savill Way Marlow Tel: +44 1628 476614 Bucks., SL7 1TH UK To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message