From owner-freebsd-stable@FreeBSD.ORG Wed Jan 5 09:02:04 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 2166C1065674 for ; Wed, 5 Jan 2011 09:02:04 +0000 (UTC) (envelope-from ml@my.gd) Received: from mail-wy0-f182.google.com (mail-wy0-f182.google.com [74.125.82.182]) by mx1.freebsd.org (Postfix) with ESMTP id B5BFC8FC14 for ; Wed, 5 Jan 2011 09:02:02 +0000 (UTC) Received: by wyf19 with SMTP id 19so15257103wyf.13 for ; Wed, 05 Jan 2011 01:02:01 -0800 (PST) Received: by 10.216.182.212 with SMTP id o62mr21269992wem.52.1294218121398; Wed, 05 Jan 2011 01:02:01 -0800 (PST) Received: from [10.129.37.231] ([92.90.16.53]) by mx.google.com with ESMTPS id i80sm11029835wej.4.2011.01.05.01.01.59 (version=TLSv1/SSLv3 cipher=RC4-MD5); Wed, 05 Jan 2011 01:01:59 -0800 (PST) References: <4D1C6F90.3080206@my.gd> <4D21E679.80002@my.gd> In-Reply-To: <4D21E679.80002@my.gd> Mime-Version: 1.0 (iPhone Mail 8A293) Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii Message-Id: <84882169-0461-480F-8B4C-58E794BCC8E6@my.gd> X-Mailer: iPhone Mail (8A293) From: Damien Fleuriot Date: Wed, 5 Jan 2011 10:01:11 +0100 To: Damien Fleuriot Cc: "freebsd-stable@freebsd.org" 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: Wed, 05 Jan 2011 09:02:04 -0000 Hi again List, I'm not so sure about using raidz2 anymore, I'm concerned for the performanc= e. Basically I have 9x 1.5T sata drives. raidz2 and 2x raidz1 will provide the same capacity. Are there any cons against using 2x raidz1 instead of 1x raidz2 ? I plan on using a SSD drive for the OS, 40-64gb, with 15 for the system itse= lf and some spare. Is it worth using the free space for cache ? ZIL ? both ? @jean-yves : didn't you experience problems recently when using both ? --- Fleuriot Damien On 3 Jan 2011, at 16:08, Damien Fleuriot wrote: >=20 >=20 > On 1/3/11 2:17 PM, Ivan Voras wrote: >> On 12/30/10 12:40, Damien Fleuriot wrote: >>=20 >>> I am concerned that in the event a drive fails, I won't be able to >>> repair the disks in time before another actually fails. >>=20 >> An old trick to avoid that is to buy drives from different series or >> manufacturers (the theory is that identical drives tend to fail at the >> same time), but this may not be applicable if you have 5 drives in a >> volume :) Still, you can try playing with RAIDZ levels and probabilities.= >>=20 >=20 > That's sound advice, although one also hears that they should get > devices from the same vendor for maximum compatibility -.- >=20 >=20 > Ah well, next time ;) >=20 >=20 > A piece of advice I shall heed though is using 1% less capacity than > what the disks really provide, in case one day I have to swap a drive > and its replacement is a few kbytes smaller (thus preventing a rebuild).