From owner-freebsd-fs@FreeBSD.ORG Mon Jun 4 20:41:21 2012 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 1EA911065689; Mon, 4 Jun 2012 20:41:21 +0000 (UTC) (envelope-from kayasaman@gmail.com) Received: from mail-ee0-f54.google.com (mail-ee0-f54.google.com [74.125.83.54]) by mx1.freebsd.org (Postfix) with ESMTP id 73EF88FC0C; Mon, 4 Jun 2012 20:41:20 +0000 (UTC) Received: by eeke49 with SMTP id e49so1836568eek.13 for ; Mon, 04 Jun 2012 13:41:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:content-type:content-transfer-encoding; bh=VRSOx86GSn/PyPy+qWgEhKoxH0vg4nemAqorbK0m5+c=; b=LLBY4e9naCCsE+kQf0c6m4s5vF2qUaCcL8WLWw2fgAesZ/ykWlsml6Eb48G5q9EXc4 8CikQW955sfBV7D0E5beXUPQ5/3SeYuIyNGQjRidfzkYrcaIhdnP4xn4X5UD5eSeVfcD Bq+JvzWcML97Lx3lqbBfCNI4FSsfIFmzk7u+etLWQORd4sIdjBpUoPMNcLd+VBrLyZiK khLIMBjPjqa++vKWSG1PQjx7eytgbU4HybHZM74P8+K3H5CAy1qsI4MLyl0elTiDJOdX qM1gbcJAZ/tr5yipmyRv1mX/Br2dkpWA9BHDaCJ/ac9C/82UCdnTV7z9EUFKsY87FyPm gqsw== Received: by 10.14.186.14 with SMTP id v14mr5935671eem.49.1338842479326; Mon, 04 Jun 2012 13:41:19 -0700 (PDT) Received: from X220.optiplex-networks.com (81-178-2-118.dsl.pipex.com. [81.178.2.118]) by mx.google.com with ESMTPS id g51sm41085209eea.14.2012.06.04.13.41.17 (version=SSLv3 cipher=OTHER); Mon, 04 Jun 2012 13:41:18 -0700 (PDT) Message-ID: <4FCD1D6B.9030901@gmail.com> Date: Mon, 04 Jun 2012 21:41:15 +0100 From: Kaya Saman User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:12.0) Gecko/20120430 Thunderbird/12.0.1 MIME-Version: 1.0 To: Matthew Seaman References: <4FCD13CF.3010406@gmail.com> <4FCD17C6.5020503@FreeBSD.org> <4FCD19E6.1010802@gmail.com> <4FCD1CD4.5080406@FreeBSD.org> In-Reply-To: <4FCD1CD4.5080406@FreeBSD.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: freebsd-fs@FreeBSD.org Subject: Re: Using ZFS as RAID0 - disk offline question X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 04 Jun 2012 20:41:21 -0000 On 06/04/2012 09:38 PM, Matthew Seaman wrote: > On 04/06/2012 21:26, Kaya Saman wrote: >> You see if say a system board fails and both devices are named /dev/ad4 >> and /dev/ad5 then a new system board gets put in and the device names >> changed to /dev/ad12 and /dev/ad13 my question is will the ZPOOL still >> exist? Will ZFS be intelligent enough to pick up the new device names >> via the disk ID's? > Yes, this should work just fine. ZFS labels each disk with its own UUID > value, so you can pretty much shuffle the disks in any order across all > available disk slots, and ZFS will be able to put the zpool back together. > >> Additionally if /dev/ad5 goes down, is it possible to keep using >> /dev/ad4 which is part of the 'downed' pool...?? Or would one need to >> replace the disk ad5 then the pool comes up again with only the >> information on ad4?? > No. A RAID0 zpool will be marked offline if any of the drives within it > fails. You might be able to recover some data from remaining drives, > but not easily. The surest way of getting anything back would be to go > to a specialist disaster recovery company, but expect to pay $$$ for it. > Considering the price of hard drives nowadays, this would be a dumb > choice: you could easily convert your RAID0 to a RAID10 for much less > than it would cost you to try and recover from a broken RAID0. > > Even if you do install a replacement disk, ZFS won't be able to rebuild > from your original drive. You'ld have to wipe and rebuild from scratch. > > Cheers, > > Matthew > Many thanks! They were exactly the answers I was looking for :-) Apologies for my inexperience in this matter! Regards, Kaya