From owner-freebsd-questions@FreeBSD.ORG Sat Oct 17 18:49:33 2009 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 CB3121065670 for ; Sat, 17 Oct 2009 18:49:33 +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 62C5C8FC1B for ; Sat, 17 Oct 2009 18:49:33 +0000 (UTC) Received: from happy-idiot-talk.infracaninophile.co.uk (localhost [IPv6:::1]) (authenticated bits=0) by smtp.infracaninophile.co.uk (8.14.3/8.14.3) with ESMTP id n9HInQsX064774; Sat, 17 Oct 2009 19:49:27 +0100 (BST) (envelope-from m.seaman@infracaninophile.co.uk) X-DKIM: Sendmail DKIM Filter v2.8.3 smtp.infracaninophile.co.uk n9HInQsX064774 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=infracaninophile.co.uk; s=200708; t=1255805367; bh=gOhsE65esqTpTxyri/3tgeX5ZAOACcw9GchJSCEJXR8=; 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<4ADA11AD.3070101@infracaninophile.co.uk>|Date:=20S at,=2017=20Oct=202009=2019:49:17=20+0100|From:=20Matthew=20Seaman= 20|Organization:=20Infracaninophi le|User-Agent:=20Thunderbird=202.0.0.23=20(X11/20090823)|MIME-Vers ion:=201.0|To:=20Jeronimo=20Calvo=20|CC:=20FreeBSD=20Questions=20|Subj ect:=20Re:=20Data=20Redundancy=20RAID=200+1=20Vs=201+0=20FREEBSD=2 07.4=20STABLE|References:=20|In-Reply-To:=20|X-Enigmail-Version:=200.95.6|Co ntent-Type:=20multipart/signed=3B=20micalg=3Dpgp-sha256=3B=0D=0A=2 0protocol=3D"application/pgp-signature"=3B=0D=0A=20boundary=3D"--- ---------enigDB3441485DA6BD533F7C668D"; b=CIRVr6RxZteB4BrQ9KlcAmA6A8HSEWQB13xsGPGPNDnmva75jVxkTMjuL8dCaWb9d SmU+BdgJnUg8t73ShSxR1smx7f/CXu4HqOk143flXLV35inCIqLV+QSQBTj6xfcoHn NyqevZufCZMoPpUmsn1j+4pmkKFOHMeUWpP4+FoE= X-Authentication-Warning: happy-idiot-talk.infracaninophile.co.uk: Host localhost [IPv6:::1] claimed to be happy-idiot-talk.infracaninophile.co.uk Message-ID: <4ADA11AD.3070101@infracaninophile.co.uk> Date: Sat, 17 Oct 2009 19:49:17 +0100 From: Matthew Seaman Organization: Infracaninophile User-Agent: Thunderbird 2.0.0.23 (X11/20090823) MIME-Version: 1.0 To: Jeronimo Calvo References: In-Reply-To: X-Enigmail-Version: 0.95.6 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="------------enigDB3441485DA6BD533F7C668D" X-Virus-Scanned: clamav-milter 0.95.2 at 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 Questions Subject: Re: Data Redundancy RAID 0+1 Vs 1+0 FREEBSD 7.4 STABLE 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: Sat, 17 Oct 2009 18:49:34 -0000 This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enigDB3441485DA6BD533F7C668D Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: quoted-printable Jeronimo Calvo wrote: > Hi folks, >=20 > I'm thinking to build a Raid on my system and I'm getting documented > abut 0+1 and 1+0 RAID systems. > As far as I can see the best option is a 1+0 is the best option as if > one of the from mirrors fails, the RAID still be redundant and in the > case of a 0+1 RAID, If one of them fails, the RAID will be down until > u replace the HD in question... >=20 > So my question is, if I am right above, what are de benefits of > mounting a RAID 0+1 ?? For workloads that involve streaming large volumes of sequential data RAID 0+1 can perform very well. However, for the typical sort of workloa= ds seen on a general purpose workstation, it offers no advantages over RAID1= 0, and for the sort of workload you get with RDBMSes -- lots of randomly scattered small IOs -- RAID10 does the business. Given the poor resilience characteristics of RAID 0+1 the sequential data streaming workload would be better handled by RAID5(0) or RAID6(0) p= lus a good hardware RAID controller with plenty of battery backed cache RAM. Cheers, Matthew --=20 Dr Matthew J Seaman MA, D.Phil. 7 Priory Courtyard Flat 3 PGP: http://www.infracaninophile.co.uk/pgpkey Ramsgate Kent, CT11 9PW --------------enigDB3441485DA6BD533F7C668D Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.13 (FreeBSD) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iEYEAREIAAYFAkraEbYACgkQ8Mjk52CukIyZAwCdGcHvGUcnCfpzgIo7D81pxz/r 3+EAnjbeJkZOpHmYlkpHVoQko1P3K+fb =s5k9 -----END PGP SIGNATURE----- --------------enigDB3441485DA6BD533F7C668D--