From owner-freebsd-current@FreeBSD.ORG Tue Jul 15 09:43:13 2008 Return-Path: Delivered-To: current@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id ADD88106566C; Tue, 15 Jul 2008 09:43:13 +0000 (UTC) (envelope-from roberto@keltia.freenix.fr) Received: from keltia.freenix.fr (keltia.freenix.org [IPv6:2001:660:330f:f820:213:72ff:fe15:f44]) by mx1.freebsd.org (Postfix) with ESMTP id 507698FC18; Tue, 15 Jul 2008 09:43:13 +0000 (UTC) (envelope-from roberto@keltia.freenix.fr) Received: from localhost (localhost [127.0.0.1]) by keltia.freenix.fr (Postfix/TLS) with ESMTP id 19A9839B11; Tue, 15 Jul 2008 11:43:11 +0200 (CEST) X-Virus-Scanned: amavisd-new at keltia.freenix.fr Received: from keltia.freenix.fr ([127.0.0.1]) by localhost (keltia.freenix.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id HDEgJ0pzKA6X; Tue, 15 Jul 2008 11:43:10 +0200 (CEST) Received: by keltia.freenix.fr (Postfix/TLS, from userid 101) id B084639ACB; Tue, 15 Jul 2008 11:43:10 +0200 (CEST) Date: Tue, 15 Jul 2008 11:43:10 +0200 From: Ollivier Robert To: src-committers@FreeBSD.org, "current@freebsd.org" Message-ID: <20080715094310.GA70666@keltia.freenix.fr> References: <200807131153.m6DBrDkX067657@repoman.freebsd.org> <487C6A86.20508@FreeBSD.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <487C6A86.20508@FreeBSD.org> X-Operating-System: MacOS X / Macbook Pro - FreeBSD 7 / Dell D820 SMP User-Agent: Mutt/1.5.17 (2007-11-01) Cc: Subject: Re: geom_mirror silently upgrading metadata [Was: cvs commit: src UPDATING] X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 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: Tue, 15 Jul 2008 09:43:13 -0000 According to Maxim Sobolev: > Not really relevant to the change in question, but I think that the whole > idea of geom_mirror updating on-disk metadata automagically is not very > well thought out. For example one could try booting 7.x kernel on 6.x > system just to see how well it goes with the intention to revert back if it > doesn't work out well. We have excellent tool called nextboot (8) that > really helps doing it safely or semi-safely even remotely over ssh. In the > worst case you just need to cycle the power to return to the previous > configuration. > > Automatic conversion makes it impossible to go back without some heavy > manual intervention at console necessary to boot off the disk directly and > re-creating/re-syncing the mirror after that. I've run into exactly this > issue today, with the target machine stuck in unbootable state on another > continent many thousand miles away. I completely agree on that one, I got bitten by this during my upgrade from 6.1-STABLE to 7.0-RELEASE on a gmirror-ed machine. That is a complete violation from POLA and harmful to say the least. -- Ollivier ROBERT -=- FreeBSD: The Power to Serve! -=- roberto@keltia.freenix.fr Darwin sidhe.keltia.net Version 9.2.0: Tue Feb 5 16:13:22 PST 2008; i386