From owner-freebsd-stable@FreeBSD.ORG Fri Jun 14 08:02:22 2013 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id D57761D8 for ; Fri, 14 Jun 2013 08:02:22 +0000 (UTC) (envelope-from doconnor@gsoft.com.au) Received: from cain.gsoft.com.au (cain.gsoft.com.au [203.31.81.10]) by mx1.freebsd.org (Postfix) with ESMTP id 456B41A78 for ; Fri, 14 Jun 2013 08:02:21 +0000 (UTC) Received: from [10.109.44.188] ([1.125.234.7]) (authenticated bits=0) by cain.gsoft.com.au (8.14.4/8.14.3) with ESMTP id r5E82562005764 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=NO); Fri, 14 Jun 2013 17:32:11 +0930 (CST) (envelope-from doconnor@gsoft.com.au) Subject: Re: zpool labelclear destroys GPT data Mime-Version: 1.0 (Mac OS X Mail 6.5 \(1508\)) Content-Type: text/plain; charset=us-ascii From: "Daniel O'Connor" In-Reply-To: <51BAC7D1.70208@gmail.com> Date: Fri, 14 Jun 2013 17:32:06 +0930 Content-Transfer-Encoding: quoted-printable Message-Id: <0A53B6AA-9614-42E9-8AA1-82233426EEE6@gsoft.com.au> References: <51B9BB14.6020103@gmail.com> <51BA381C.8070900@gmail.com> <51BAC7D1.70208@gmail.com> To: Johan Hendriks X-Mailer: Apple Mail (2.1508) X-Spam-Score: -0.272 () BAYES_00,RDNS_NONE X-Scanned-By: MIMEDefang 2.67 on 203.31.81.10 Cc: Kimmo Paasiala , freebsd-stable X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 14 Jun 2013 08:02:22 -0000 On 14/06/2013, at 17:05, Johan Hendriks wrote: >> Of course, zpool(8) will do exactly what you tell it to do. It does >> not know about any partitioning schemes and assumes that the user >> knows that using labelclear on a the whole disk will potentially >> destroy all data on it including any partitioning information. >>=20 > Well as i found out, zpool(8) does not know what it clears. ! :D >=20 > I think an adjustment to the man page is in order here. > The man page clearly state it removes ZFS labels, not GPT, gmirror and = glabel labels. > It should mention it will remove labels from the disk/device, and that = it clears ALL labels. >=20 > If a user reads the man page it now looks save to use labelclear. > I thougt that zpool would know if there was zpool label information on = the disk, and if i a case there is no ZFS label information it will tell = me that! > In my case i did not loose anything, so no big deal but there will = proberbly be someone who gets bitten by this. >=20 > A plus is that i found a new way to clear my disks fast ! ;) It only clears ZFS labels, just because GPT & gmirror information sits = in a similar place doesn't make that incorrect. You are saying the equivalent of.. Why does "dd if=3D/dev/zero of=3D/dev/da0" erase my whole disk, not just = the first partition? ie you are giving the tool bad options and then complaining when it = doesn't do what you meant :) Perhaps it should be modified to check if there is valid ZFS data there = before proceeding (although that could be annoying unless there is a way = to force it), and/or the man page could be amended to say it doesn't do = any checks before erasing things. -- Daniel O'Connor software and network engineer for Genesis Software - http://www.gsoft.com.au "The nice thing about standards is that there are so many of them to choose from." -- Andrew Tanenbaum GPG Fingerprint - 5596 B766 97C0 0E94 4347 295E E593 DC20 7B3F CE8C