Date: Tue, 15 Jul 2008 11:43:10 +0200 From: Ollivier Robert <roberto@keltia.freenix.fr> To: src-committers@FreeBSD.org, "current@freebsd.org" <current@FreeBSD.org> Subject: Re: geom_mirror silently upgrading metadata [Was: cvs commit: src UPDATING] Message-ID: <20080715094310.GA70666@keltia.freenix.fr> In-Reply-To: <487C6A86.20508@FreeBSD.org> References: <200807131153.m6DBrDkX067657@repoman.freebsd.org> <487C6A86.20508@FreeBSD.org>
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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
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