From owner-freebsd-geom@FreeBSD.ORG Mon Jun 2 18:01:17 2014 Return-Path: Delivered-To: geom@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id E1EBA67F; Mon, 2 Jun 2014 18:01:17 +0000 (UTC) Received: from h2.funkthat.com (gate2.funkthat.com [208.87.223.18]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "funkthat.com", Issuer "funkthat.com" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id A1D20231B; Mon, 2 Jun 2014 18:01:17 +0000 (UTC) Received: from h2.funkthat.com (localhost [127.0.0.1]) by h2.funkthat.com (8.14.3/8.14.3) with ESMTP id s52I18YO023225 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Mon, 2 Jun 2014 11:01:09 -0700 (PDT) (envelope-from jmg@h2.funkthat.com) Received: (from jmg@localhost) by h2.funkthat.com (8.14.3/8.14.3/Submit) id s52I183H023224; Mon, 2 Jun 2014 11:01:08 -0700 (PDT) (envelope-from jmg) Date: Mon, 2 Jun 2014 11:01:08 -0700 From: John-Mark Gurney To: "Michael W. Lucas" Subject: Re: diskid documentation Message-ID: <20140602180108.GX43976@funkthat.com> Mail-Followup-To: "Michael W. Lucas" , Ryan Stone , geom@freebsd.org, FreeBSD Current , Allan Jude References: <20140601134147.GA99583@bewilderbeast.blackhelicopters.org> <538C7B71.20109@freebsd.org> <20140602153651.GB4116@bewilderbeast.blackhelicopters.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140602153651.GB4116@bewilderbeast.blackhelicopters.org> User-Agent: Mutt/1.4.2.3i X-Operating-System: FreeBSD 7.2-RELEASE i386 X-PGP-Fingerprint: 54BA 873B 6515 3F10 9E88 9322 9CB1 8F74 6D3F A396 X-Files: The truth is out there X-URL: http://resnet.uoregon.edu/~gurney_j/ X-Resume: http://resnet.uoregon.edu/~gurney_j/resume.html X-TipJar: bitcoin:13Qmb6AeTgQecazTWph4XasEsP7nGRbAPE X-to-the-FBI-CIA-and-NSA: HI! HOW YA DOIN? can i haz chizburger? X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.2.2 (h2.funkthat.com [127.0.0.1]); Mon, 02 Jun 2014 11:01:09 -0700 (PDT) Cc: geom@freebsd.org, FreeBSD Current , Ryan Stone , Allan Jude X-BeenThere: freebsd-geom@freebsd.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: GEOM-specific discussions and implementations List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 02 Jun 2014 18:01:18 -0000 Michael W. Lucas wrote this message on Mon, Jun 02, 2014 at 11:36 -0400: > On Mon, Jun 02, 2014 at 10:45:52AM -0400, Ryan Stone wrote: > > On Mon, Jun 2, 2014 at 9:26 AM, Allan Jude wrote: > > > It also tends to sometimes hide the gpt label provider on me (not sure > > > in which cases it does this, but it is annoying) > > > > This happens when something (e.g. zfs) happens to open the diskid > > provider instead of the gpt label. For me this ended up being a bit > > more than annoying; my swap was mounted in /etc/fstab via a gpt label > > so I silently lost my swap when I did an upgrade. > > Wait-- one type of one label can hide another? > > I thought a big point of labels was to remove ambiguity... Surprisingly, yes... I didn't think about this, but it's true... A disk will get exported via two different devices, diskid and normal da/ada... The tasting will go through and create all the necessary sub devices, but the problem is that we now have two different paths, and if something opens the diskid path, then the da/ada paths all disappear... This sounds like we need to fix geom to "bind" the two together so that when one opens, the other doesn't disappear... The problem is that geom views them as two separate disks when in fact they are the same... someone who knows geom well should think about how to solve this problem, as diskid isn't the first time this has happened, just most prevalent w/ ZFS and diskid. -- John-Mark Gurney Voice: +1 415 225 5579 "All that I will do, has been done, All that I have, has not."