From owner-freebsd-questions@FreeBSD.ORG Wed Aug 6 09:55:06 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 12AD11065674 for ; Wed, 6 Aug 2008 09:55:06 +0000 (UTC) (envelope-from m.seaman@infracaninophile.co.uk) Received: from smtp.infracaninophile.co.uk (gate6.infracaninophile.co.uk [IPv6:2001:8b0:151:1::1]) by mx1.freebsd.org (Postfix) with ESMTP id 67C4D8FC14 for ; Wed, 6 Aug 2008 09:55:05 +0000 (UTC) (envelope-from m.seaman@infracaninophile.co.uk) Received: from happy-idiot-talk.infracaninophile.co.uk (localhost [IPv6:::1]) (authenticated bits=0) by smtp.infracaninophile.co.uk (8.14.2/8.14.2) with ESMTP id m769svAL086564; Wed, 6 Aug 2008 10:54:59 +0100 (BST) (envelope-from m.seaman@infracaninophile.co.uk) X-DKIM: Sendmail DKIM Filter v2.7.0 smtp.infracaninophile.co.uk m769svAL086564 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=infracaninophile.co.uk; s=200708; t=1218016499; bh=KFJNrYKH3Eam5d KASrI1uJ6Rpy8/6i78vHjdIIX59V4=; h=Message-ID:Date:From:MIME-Version: To:CC:Subject:References:In-Reply-To:Content-Type:Cc:Content-Type: Date:From:In-Reply-To:Message-ID:Mime-Version:References:To; z=Mes sage-ID:=20<489974EB.3070505@infracaninophile.co.uk>|Date:=20Wed,=2 006=20Aug=202008=2010:54:51=20+0100|From:=20Matthew=20Seaman=20|Organization:=20Infracaninophile|User -Agent:=20Thunderbird=202.0.0.16=20(X11/20080726)|MIME-Version:=201 .0|To:=20Gary=20Kline=20|CC:=20FreeBSD=20Mailing =20List=20|Subject:=20Re:=20general= 20questions=20about=207.0=20and=20computer=20efficiency......|Refer ences:=20<20080805181926.GA24000@thought.org>|In-Reply-To:=20<20080 805181926.GA24000@thought.org>|X-Enigmail-Version:=200.95.6|Content -Type:=20multipart/signed=3B=20micalg=3Dpgp-sha256=3B=0D=0A=20proto col=3D"application/pgp-signature"=3B=0D=0A=20boundary=3D"---------- --enig834A45F56EA7AF6D20C1D0EC"; b=ksxOfzmHo193c/wV/Mln/xmGNCDNg911 SNN52BcJ9SBUwoh1n/kjZVFCzifXe8vD0eAo4XUt+XtYeXBnuQhlwZdiHWuUjHu9VHS UeSbit4jqv/SUZR6h0fhe0ybeNmje/1W3+ATAemwmwcWnqGMnq5KqKayXXVuZupPPPc 1c8ng= Message-ID: <489974EB.3070505@infracaninophile.co.uk> Date: Wed, 06 Aug 2008 10:54:51 +0100 From: Matthew Seaman Organization: Infracaninophile User-Agent: Thunderbird 2.0.0.16 (X11/20080726) MIME-Version: 1.0 To: Gary Kline References: <20080805181926.GA24000@thought.org> In-Reply-To: <20080805181926.GA24000@thought.org> X-Enigmail-Version: 0.95.6 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="------------enig834A45F56EA7AF6D20C1D0EC" X-Virus-Scanned: ClamAV 0.93.3/7955/Wed Aug 6 09:27:30 2008 on happy-idiot-talk.infracaninophile.co.uk X-Virus-Status: Clean X-Spam-Status: No, score=-3.0 required=5.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VERIFIED,NO_RELAYS autolearn=ham version=3.2.5 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on happy-idiot-talk.infracaninophile.co.uk Cc: FreeBSD Mailing List Subject: Re: general questions about 7.0 and computer efficiency...... 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, 06 Aug 2008 09:55:06 -0000 This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig834A45F56EA7AF6D20C1D0EC Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: quoted-printable Gary Kline wrote: > I kep track on the load on my main server, and it is rarely above > 0.20. If the load is a poor metric of power use, what is > better? (My new `Watt-o-Meter' is checking the power right now, > but I would like to know what drink the most juice: disk,RAM, > processor, OpSys? Number of hit/hours? I want my upgrades to > be as cost-effective as possible, in other words.=20 Generally, the faster anything runs the more power it consumes. It takes more energy to switch on-off (ie generate a digital pulse) the faster you try and do it. Similar considerations apply to disks --=20 the faster the platters spin and the faster you need to move the heads about, the more energy it takes. Actually, for disks the physical size of the disk has quite an effect there too: small form-factor disks as com= monly used in laptops and various HP servers are more efficient GB for GB than the equivalent 5.25" standard drives. There are exceptions to this rule -- for instance early model Xeon processors ran really hot, meaning they were power pigs. Current AMD and Core2 processors use lower voltages internally and consequently are a lot more thermodynamically efficient. If you want to save energy, there are two pretty useful strategies for the home user: * use eg. laptops -- these are carefully designed to be power efficient= in order to give the maximum battery life. They also effectively have a built-in UPS. Similarly you can use low power appliances built around specialist chipsets like the VIA Eden range. * take advantage of the massive computational power of modern high-end kit, and consolidate a number of old machines as virtual hosts on one physical server. There are several freely available host systems= you can use -- Xen is an interesting choice, but AFAIK it doesn't support FreeBSD as the *host* -- it's fine for *guests* though.=20 VMWare ESX is apparently available at zero cost as well. Unfortunately even though the running costs will be lower, the up-front=20 costs for either of these strategies will be higher than simply carrying on as before. There's also a significant 'all the eggs in one basket'=20 problem with virtualization. Cheers, Matthew PS. If you happen to be running a whole machine room, then there's a lot of energy efficiency to be recovered by looking carefully at power=20 conversion. A typical large scale UPS will run at about 85% efficiency. An individual computer power supply will usually be less efficient than that. So even before you've got to the 5 and 12V buses on your mother board, 28% or more of your input electrical power has been dispersed as heat. Then consider how a high-end UPS works. It takes in incoming 240V 50HZ AC power and internally converts it into 12 or 24V DC. Some of this powe= r goes towards charging its battery units, but the rest is /converted back to 240V 50Hz AC/ for supply to the computer PSU, which then /convert= s it back to 5 and 12V DC again/. Converting back and forth so many time= s is insane. Better for the UPS to provide low voltage DC electrical power= -- for historical reasons it's usual to provide 48V DC (the higher voltag= e means there's less transmission loss due to resistance in cabling, plus with this sort of set-up minimizing the length of cable runs is good prac= tice too). Unfortunately, trying to find a commodity PCs (even server class machines) with 48V DC PSUs is next to impossible and damnabl= y expensive even so. --=20 Dr Matthew J Seaman MA, D.Phil. 7 Priory Courtyard Flat 3 PGP: http://www.infracaninophile.co.uk/pgpkey Ramsgate Kent, CT11 9PW --------------enig834A45F56EA7AF6D20C1D0EC Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.9 (FreeBSD) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iEYEAREIAAYFAkiZdPEACgkQ8Mjk52CukIyDNgCeNFl1MbOwxcHw9A52wJknrEUQ Y3wAnjyl87pVPV5u7ihw2aMbbbIVqYRf =aXzG -----END PGP SIGNATURE----- --------------enig834A45F56EA7AF6D20C1D0EC--