From owner-freebsd-current@freebsd.org Wed Sep 28 19:02:52 2016 Return-Path: Delivered-To: freebsd-current@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id A20FEBECD6A for ; Wed, 28 Sep 2016 19:02:52 +0000 (UTC) (envelope-from allanjude@freebsd.org) Received: from mx1.scaleengine.net (mx1.scaleengine.net [209.51.186.6]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 679031350 for ; Wed, 28 Sep 2016 19:02:51 +0000 (UTC) (envelope-from allanjude@freebsd.org) Received: from [10.1.1.2] (unknown [10.1.1.2]) (Authenticated sender: allanjude.freebsd@scaleengine.com) by mx1.scaleengine.net (Postfix) with ESMTPSA id 44B371724 for ; Wed, 28 Sep 2016 19:02:50 +0000 (UTC) Subject: Re: Destroy GPT partition scheme absolutely, how? To: freebsd-current@freebsd.org References: <20160926150109.0d0d793e@hermann> <57E92726.2020605@gmail.com> <5484D815-4B17-456B-BA60-CC6F4E97AFE3@gmail.com> <1785064.lgVzRW13Wf@ralph.baldwin.cx> From: Allan Jude Message-ID: <9b345002-5fb1-5cc3-3a60-9bf872d79d21@freebsd.org> Date: Wed, 28 Sep 2016 15:02:46 -0400 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.3.0 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="TP80tKuDdF2dFwU24O5Depr353CP14j7A" X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 28 Sep 2016 19:02:52 -0000 This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --TP80tKuDdF2dFwU24O5Depr353CP14j7A Content-Type: multipart/mixed; boundary="qWCiMF8H2aEPtN4kBTEF4PAURruUbaPdL"; protected-headers="v1" From: Allan Jude To: freebsd-current@freebsd.org Message-ID: <9b345002-5fb1-5cc3-3a60-9bf872d79d21@freebsd.org> Subject: Re: Destroy GPT partition scheme absolutely, how? References: <20160926150109.0d0d793e@hermann> <57E92726.2020605@gmail.com> <5484D815-4B17-456B-BA60-CC6F4E97AFE3@gmail.com> <1785064.lgVzRW13Wf@ralph.baldwin.cx> In-Reply-To: --qWCiMF8H2aEPtN4kBTEF4PAURruUbaPdL Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable On 2016-09-27 01:58, Warner Losh wrote: > On Mon, Sep 26, 2016 at 11:06 PM, O'Connor, Daniel = wrote: >> >>> On 27 Sep 2016, at 14:28, Warner Losh wrote: >>> dd of 2MB of zeros to the start and end of the disk. That will destro= y >>> pretty much everything. For SSDs, sometimes you can do the same with >>> TRIMs only faster (other times they are slower or unreliable). >> >> Yeah, but it would be nicer to not have to know that particular magic = incarnation :) >=20 > Disk formatting has always been 3 parts magic, 2 parts luck and 1 part = skill :) >=20 > It doesn't fit nicely into geom because metadata can live elsewhere. >=20 > I forgot to add the caveat not to try this on a disk that is part of a > RAID volume. >=20 > Warner > _______________________________________________ > freebsd-current@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-current > To unsubscribe, send any mail to "freebsd-current-unsubscribe@freebsd.o= rg" >=20 I wonder if this issue is related at all to the new 'auto resize' gpart bits. That leaves the 'uncommitted' transaction pending, and may require a 'gpart undo' before the other commands will work correctly. I wonder if something like 'zpool labelclear', but for gpart would be useful, that just nukes the first and last few MB of the disk. I know in the installer we jump through a number of hoops to try to clear out old stuff, and having one command would be better. --=20 Allan Jude --qWCiMF8H2aEPtN4kBTEF4PAURruUbaPdL-- --TP80tKuDdF2dFwU24O5Depr353CP14j7A Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (MingW32) iQIcBAEBAgAGBQJX7BPZAAoJEBmVNT4SmAt+9wwP/12Nx4GvgByRyN+asAy9IiqM JsS2idfDD0oFzlc0egcKTP1g8iXgepgKoaztenZUiF9XnV2FDJMjQiEWHQgKoNIW HkANJk20+H/y9p0IP558iecXvaO7O3QuOoCZu9V0CUyyk6uh1RpTLBqI+dGzOvqp dxdJg3sesfxqcl8qAM2sjcbJSCCh2HRmBGTbCuuyLJb0RKIlvMel/lSGZcSdJzsK NI4s8E2qOaYTR+Ogju/Z5fuvzphYetu0SOl2PfmVfTHPkBnPBKk5/tdBDu/fRfIW 3JLQrv+H/kAMpX7byTzeSpwxrXf6QqOseWTX/ehwmFbB3BRzaQra97n6FlywWhBf /MKBv1jIRrU4qOVJ0OTVfBv5fw18A6NynVEBpARoUtRuRSEtXz1hKp6mkTgSZM6i Di/VhEXLv2RbR6A5NpgOSHjTYlkE+lYQ5Av7LYe6ZkDTf6YdZGrp8slZal2GVXyc 6zRgQsuofAjOJlu9pKDC1wrM1cTHfartWQQWQVsmJt2tIiex9qahikYkNIXJunN/ zwe6nVmJqgHgHZDgt128r0QIXhk4x6Q2/ReRZiZzX0GCvA5X/7CXmwBvXcp76BW/ JkI7n5y/YlWRW4+Sr9iWxM4OybIierd5Z8drSbOtTxRe0M9HP84OG466WtoBWJxT xNxWs0TukcaDl78GS0J5 =t82n -----END PGP SIGNATURE----- --TP80tKuDdF2dFwU24O5Depr353CP14j7A--