From owner-freebsd-fs@FreeBSD.ORG Tue Oct 19 21:58:32 2010 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 15CB5106564A for ; Tue, 19 Oct 2010 21:58:32 +0000 (UTC) (envelope-from wjw@digiware.nl) Received: from mail.digiware.nl (mail.ip6.digiware.nl [IPv6:2001:4cb8:1:106::2]) by mx1.freebsd.org (Postfix) with ESMTP id 9DDD18FC14 for ; Tue, 19 Oct 2010 21:58:31 +0000 (UTC) Received: from localhost (localhost.digiware.nl [127.0.0.1]) by mail.digiware.nl (Postfix) with ESMTP id E5AF1153434; Tue, 19 Oct 2010 23:58:30 +0200 (CEST) X-Virus-Scanned: amavisd-new at digiware.nl Received: from mail.digiware.nl ([127.0.0.1]) by localhost (rack1.digiware.nl [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id OlwzFulwcqrV; Tue, 19 Oct 2010 23:58:28 +0200 (CEST) Received: from [127.0.0.1] (opteron [192.168.10.67]) (using TLSv1 with cipher DHE-RSA-CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by mail.digiware.nl (Postfix) with ESMTPSA id B8452153433; Tue, 19 Oct 2010 23:58:28 +0200 (CEST) Message-ID: <4CBE1485.2070400@digiware.nl> Date: Tue, 19 Oct 2010 23:58:29 +0200 From: Willem Jan Withagen User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2.9) Gecko/20100915 Lightning/1.0b2 Thunderbird/3.1.4 MIME-Version: 1.0 To: Freddie Cash References: <20101019151602.GA61733@icarus.home.lan> <7BEF90D9F4D4CB985F3573C3@HexaDeca64.dmpriest.net.uk> <4CBDFFF6.5080701@digiware.nl> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: freebsd-fs@freebsd.org Subject: Re: ZFS 'read-only' device / pool scan / import? 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: Tue, 19 Oct 2010 21:58:32 -0000 On 2010-10-19 23:03, Freddie Cash wrote: > While using labelled devices (be it glabel, gpt label, or whatever) > certainly helps keep things ordered and working. > > However, ZFS also labels the devices in the pool. A simple "zpool > export poolname" followed by a "zpool import poolname" will scan the > metadata on the drives, find all the devices in the pool, re-order > things internally, and carry on. > > Back when I started with ZFS, I used unlabelled drives (also on 3Ware > controllers) and made the mistake once of booting with a failed drive > removed. Pool came up faulted saying all the drives after the missing > one were also faulted. Thought I lost the whole pool. However, some > digging online showed the export/import info, and I was able to > continue on without losing any data. At the moment I have two 10Tb systems available so I'm experimenting a lot to get a feeling on how easy recovering is. So your comments are well appreciated. And your suggestion is that although things looked really messed up, just export/import fixed the lot.... The GPT trick is sort of selfdocumenting, because it is otherwise real easy to get lost with 10 disks and 4 flash-devices. :( And just because I yanked a single log disk (the wrong one) I ended up with a corrupt zraid. So the least lesson for me here (again) has been that disk handling requires the utmost care. Trouble is just around the corner. --WjW