From owner-freebsd-stable@FreeBSD.ORG Sun Jan 9 12:06:23 2011 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 51C75106564A for ; Sun, 9 Jan 2011 12:06:23 +0000 (UTC) (envelope-from m.seaman@infracaninophile.co.uk) Received: from smtp.infracaninophile.co.uk (smtp6.infracaninophile.co.uk [IPv6:2001:8b0:151:1:3fd3:cd67:fafa:3d78]) by mx1.freebsd.org (Postfix) with ESMTP id AB08F8FC08 for ; Sun, 9 Jan 2011 12:06:22 +0000 (UTC) Received: from seedling.black-earth.co.uk (seedling.black-earth.co.uk [81.187.76.163]) (authenticated bits=0) by smtp.infracaninophile.co.uk (8.14.4/8.14.4) with ESMTP id p09C6Has064568 (version=TLSv1/SSLv3 cipher=DHE-RSA-CAMELLIA256-SHA bits=256 verify=NO); Sun, 9 Jan 2011 12:06:18 GMT (envelope-from m.seaman@infracaninophile.co.uk) X-DKIM: Sendmail DKIM Filter v2.8.3 smtp.infracaninophile.co.uk p09C6Has064568 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=infracaninophile.co.uk; s=201001-infracaninophile; t=1294574778; bh=sfxHftCu1NlZX42Vhw0hrd/q0XW2fR4yDW0Xw7PHdAw=; 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=Message-ID:=20<4D29A4B2.5090902@infracaninophile.co.uk>|Date:=20S un,=2009=20Jan=202011=2012:06:10=20+0000|From:=20Matthew=20Seaman= 20|User-Agent:=20Mozilla/5.0=20(M acintosh=3B=20U=3B=20Intel=20Mac=20OS=20X=2010.6=3B=20en-US=3B=20r v:1.9.2.13)=20Gecko/20101207=20Thunderbird/3.1.7|MIME-Version:=201 .0|To:=20"Patrick=20M.=20Hausen"=20|CC:=20Jean-Yv es=20Avenard=20,=20freebsd-stable@freebsd.org |Subject:=20Re:=20ZFS=20-=20moving=20from=20a=20zraid1=20to=20zrai d2=20pool=20with=201.5tb=20disks|References:=20<4D1C6F90.3080206@m y.gd>=09=09<4D21E679.80002@my.gd>=09 <84882169-0461-480F-8B4C-58E794BCC8E6@my.gd>=09=09=09<4D297587.4030108@infracaninophile.co.uk>=20=20<4D2987E0 .7060701@infracaninophile.co.uk>=20<5F1A810A-E5B9-420E-89C1-4316A0 4B9A75@punkt.de>|In-Reply-To:=20<5F1A810A-E5B9-420E-89C1-4316A04B9 A75@punkt.de>|X-Enigmail-Version:=201.1.1|OpenPGP:=20id=3D60AE908C |Content-Type:=20multipart/signed=3B=20micalg=3Dpgp-sha1=3B=0D=0A= 20protocol=3D"application/pgp-signature"=3B=0D=0A=20boundary=3D"-- ----------enigC11367E7E0A1CBE808F8CE86"; b=xCab1Eq7Yr/X86P8Xi4yRL8J1xcOZxYx7cb5yQByavok632iXIwn76MSndiWtTHWR Fe4yXxtBFK+ifz3+eH56/gSCheI9zlN0RXdxGjssBjnmh00BUc7NvAPp1VLFtewHEY vbmGrLK6bivPDqQyYbyRGRqSEjtYzpvDkZMPS7vY= Message-ID: <4D29A4B2.5090902@infracaninophile.co.uk> Date: Sun, 09 Jan 2011 12:06:10 +0000 From: Matthew Seaman User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-US; rv:1.9.2.13) Gecko/20101207 Thunderbird/3.1.7 MIME-Version: 1.0 To: "Patrick M. Hausen" References: <4D1C6F90.3080206@my.gd> <4D21E679.80002@my.gd> <84882169-0461-480F-8B4C-58E794BCC8E6@my.gd> <4D297587.4030108@infracaninophile.co.uk> <4D2987E0.7060701@infracaninophile.co.uk> <5F1A810A-E5B9-420E-89C1-4316A04B9A75@punkt.de> In-Reply-To: <5F1A810A-E5B9-420E-89C1-4316A04B9A75@punkt.de> X-Enigmail-Version: 1.1.1 OpenPGP: id=60AE908C Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enigC11367E7E0A1CBE808F8CE86" X-Virus-Scanned: clamav-milter 0.96.5 at lucid-nonsense.infracaninophile.co.uk X-Virus-Status: Clean X-Spam-Status: No, score=-0.1 required=5.0 tests=BAYES_20,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,SPF_FAIL autolearn=no version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on lucid-nonsense.infracaninophile.co.uk Cc: freebsd-stable@freebsd.org, Jean-Yves Avenard Subject: Re: ZFS - moving from a zraid1 to zraid2 pool with 1.5tb disks X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 09 Jan 2011 12:06:23 -0000 This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enigC11367E7E0A1CBE808F8CE86 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 09/01/2011 10:14, Patrick M. Hausen wrote: > I assume you are familiar with these papers? >=20 > http://queue.acm.org/detail.cfm?id=3D1317403 > http://queue.acm.org/detail.cfm?id=3D1670144 >=20 > Short version: as hard disk sizes increase to 2 TB and beyond while the= URE rate > stays in the order of 1 to 10^14 blocks read, the probability of encoun= tering an URE > during rebuild of a single parity RAID approaches 1. Yes. Rotating magnetic media seems to be bumping up against some intrinsic performance/reliability limits to the year-on-year doubling of capacity. Having to add more and more "extra" drives to ensure the same level of reliability is not a wining proposition in the long term. Roll on solid state storage. I particularly like the sound of HP and Hynix's memristor technology. If memristors pan out, then they are going to replace both D-RAM and hard drives, and eventually replace transistors as the basic building block for electronic logic circuits. Five to ten years from now, hardware design is going to be very different, and the software that runs on it will have to be radically redesigned to match. Think what that means. * You don't have to *save* a file, ever. If it's in memory, it's in persistent storage. * The effect on RDBMS performance is going to be awesome -- none of that time consuming waiting for sync-to-disk. * A computer should be able to survive a power outage of a few seconds and carry on where it left off, without specially going into hibernation mode. * Similarly, "reboot" will be at the flick of a switch -- pretty much instant on. * Portables will look a lot more like iPads or other tablet devices, and will have battery lifetimes of several days. About the only significant difference is one will have a hinge down the middle and a built-in keyboard, while the other will only have the touch screen. Oh, and let's not forget the beneficial effects of *no moving parts* and *lower power consumption* on system reliability. Now all we need are the telcos to lay multi-Gb/s capacity fibre to every house and business, and things will start to get very interesting indeed. Cheers Matthew --=20 Dr Matthew J Seaman MA, D.Phil. 7 Priory Courtyard Flat 3 PGP: http://www.infracaninophile.co.uk/pgpkey Ramsgate JID: matthew@infracaninophile.co.uk Kent, CT11 9PW --------------enigC11367E7E0A1CBE808F8CE86 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG/MacGPG2 v2.0.16 (Darwin) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAk0ppLkACgkQ8Mjk52CukIwM5gCfZYXra54vwn1OMjdJ3Rs0mxuK p+QAn0Oi8fnHVI04ZQEfoqZWdCrnxGwS =rqGc -----END PGP SIGNATURE----- --------------enigC11367E7E0A1CBE808F8CE86--