From owner-freebsd-stable@FreeBSD.ORG Thu Jan 6 09:20:51 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 D7C141065694 for ; Thu, 6 Jan 2011 09:20:51 +0000 (UTC) (envelope-from ml@my.gd) Received: from mail-ww0-f50.google.com (mail-ww0-f50.google.com [74.125.82.50]) by mx1.freebsd.org (Postfix) with ESMTP id 725A38FC14 for ; Thu, 6 Jan 2011 09:20:51 +0000 (UTC) Received: by wwf26 with SMTP id 26so15981669wwf.31 for ; Thu, 06 Jan 2011 01:20:50 -0800 (PST) Received: by 10.216.213.15 with SMTP id z15mr23189948weo.61.1294305650277; Thu, 06 Jan 2011 01:20:50 -0800 (PST) Received: from [192.168.0.20] (paris.c-mal.com [88.170.200.60]) by mx.google.com with ESMTPS id j49sm10452561wer.38.2011.01.06.01.20.47 (version=TLSv1/SSLv3 cipher=RC4-MD5); Thu, 06 Jan 2011 01:20:49 -0800 (PST) References: <4D1C6F90.3080206@my.gd> <4D21E679.80002@my.gd> <84882169-0461-480F-8B4C-58E794BCC8E6@my.gd> <488AE93A-97B9-4F01-AD0A-0098E4B329C3@my.gd> In-Reply-To: Mime-Version: 1.0 (iPhone Mail 8A293) Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii Message-Id: X-Mailer: iPhone Mail (8A293) From: Damien Fleuriot Date: Thu, 6 Jan 2011 10:20:00 +0100 To: Artem Belevich Cc: "freebsd-stable@freebsd.org" , Chris Forgeron 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: Thu, 06 Jan 2011 09:20:51 -0000 You both make good points, thanks for the feedback :) I am more concerned about data protection than performance, so I suppose rai= dz2 is the best choice I have with such a small scale setup. Now the question that remains is wether or not to use parts of the OS's ssd f= or zil, cache, or both ? --- Fleuriot Damien On 5 Jan 2011, at 23:12, Artem Belevich wrote: > On Wed, Jan 5, 2011 at 1:55 PM, Damien Fleuriot wrote: >> Well actually... >>=20 >> raidz2: >> - 7x 1.5 tb =3D 10.5tb >> - 2 parity drives >>=20 >> raidz1: >> - 3x 1.5 tb =3D 4.5 tb >> - 4x 1.5 tb =3D 6 tb , total 10.5tb >> - 2 parity drives in split thus different raidz1 arrays >>=20 >> So really, in both cases 2 different parity drives and same storage... >=20 > In second case you get better performance, but lose some data > protection. It's still raidz1 and you can't guarantee functionality in > all cases of two drives failing. If two drives fail in the same vdev, > your entire pool will be gone. Granted, it's better than single-vdev > raidz1, but it's *not* as good as raidz2. >=20 > --Artem