From owner-freebsd-current@freebsd.org Wed Sep 28 19:29:33 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 25C57C006D5 for ; Wed, 28 Sep 2016 19:29:33 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: from mail-it0-x233.google.com (mail-it0-x233.google.com [IPv6:2607:f8b0:4001:c0b::233]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id DEE35BE for ; Wed, 28 Sep 2016 19:29:32 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: by mail-it0-x233.google.com with SMTP id r192so132351848ita.0 for ; Wed, 28 Sep 2016 12:29:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bsdimp-com.20150623.gappssmtp.com; s=20150623; h=mime-version:sender:in-reply-to:references:from:date:message-id :subject:to:cc; bh=apv6p54UVcGj3jbWow0sDEu+z7bstylEZU8BAZq5Ycs=; b=TgtuWyWda1+RvIurwVpmz5graQt5YtpQf/1xFMX9Q6pS7Kw0ugCzngT+DVGdhswisk lTi1pD43cq09wloFo8moSocBd9S/LaIaCu7SHXGRj54ZXNXnuKQeyuPz/DYug3NjYOLv 6JnP5Ul13VNngUdMQU6Tw3P66K59YQp9JiIH+BBwzpDJchQB2c2iQwRCdluBF8hNXamO Kf89XnuGL1tUuGGdLPOayjROu6Z93JH+KWTFhh/gFtJICY2DY52ZgmZT8VKdjhwRlGx/ 4Jfgw2hoRO+RGz3/YmmXts2uM6lFU1NjdS1leN95Sjxhm6Fw2r9pobw5NA9zaD9/pfdi fb+Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:sender:in-reply-to:references:from :date:message-id:subject:to:cc; bh=apv6p54UVcGj3jbWow0sDEu+z7bstylEZU8BAZq5Ycs=; b=Q2MIi7h4YrfwP6CqRRRmEzKoHHgpJ0nLU1q6Q9KmnAL9Gw0rMP7cJHPWBDmjFboQr6 DVp3W2kmWJs1qDVhelOpHBoDbxIU9YCIvQZcBiWV3qc/fogvjHbFQELw04MpqOb4P/4s MSbbC64Ir+q8ledTdf4nfhXZF1L9Ls0IuUlNqi7oVj2mBZ6fdKahu2jOKJX32og5DK1Z kNr72EofMZhTfYncKlQVn0zoXccfwWmNWlQ4GTkb2pJvhwiJwnebj9s1Ly5UAO+GdC4P Emb5wmeZ159uVrhpgzyxlLe8GtWhIFM5OKpWBEDpnbyzNe2sF7dLJNEVrcVkidV/4k8n tc5g== X-Gm-Message-State: AA6/9Rlp++HOYDm3YIMuILLB2FwENlExoli5aPl8gc5EuM/+SDbUWPAMW1kbNjq4eLVdC7KYyqHKRCebiU108g== X-Received: by 10.107.163.72 with SMTP id m69mr40045262ioe.106.1475090972242; Wed, 28 Sep 2016 12:29:32 -0700 (PDT) MIME-Version: 1.0 Sender: wlosh@bsdimp.com Received: by 10.36.65.7 with HTTP; Wed, 28 Sep 2016 12:29:31 -0700 (PDT) X-Originating-IP: [69.53.245.200] In-Reply-To: <9b345002-5fb1-5cc3-3a60-9bf872d79d21@freebsd.org> References: <20160926150109.0d0d793e@hermann> <57E92726.2020605@gmail.com> <5484D815-4B17-456B-BA60-CC6F4E97AFE3@gmail.com> <1785064.lgVzRW13Wf@ralph.baldwin.cx> <9b345002-5fb1-5cc3-3a60-9bf872d79d21@freebsd.org> From: Warner Losh Date: Wed, 28 Sep 2016 13:29:31 -0600 X-Google-Sender-Auth: RNuRdBfmKb6oP2tI-Cq68GWVMy4 Message-ID: Subject: Re: Destroy GPT partition scheme absolutely, how? To: Allan Jude Cc: FreeBSD Current Content-Type: text/plain; charset=UTF-8 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 19:29:33 -0000 On Wed, Sep 28, 2016 at 1:02 PM, Allan Jude wrote: > 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 destroy >>>> 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 :) >> >> Disk formatting has always been 3 parts magic, 2 parts luck and 1 part skill :) >> >> It doesn't fit nicely into geom because metadata can live elsewhere. >> >> I forgot to add the caveat not to try this on a disk that is part of a >> RAID volume. >> >> 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.org" >> > > 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. I thought the auto resize stuff was backed out, precisely because it left bogons around... Warner