Date: Sat, 28 Jun 2008 08:03:52 +0200 From: Oliver Brandmueller <ob@e-Gitt.NET> To: freebsd-stable@freebsd.org Cc: Peter Jeremy <peterjeremy@optushome.com.au> Subject: Re: GEOM gotcha upgrading from 6.x to 7.x Message-ID: <20080628060352.GZ6902@e-Gitt.NET> In-Reply-To: <20080627214912.GB50631@server.vk2pj.dyndns.org> References: <20080627214912.GB50631@server.vk2pj.dyndns.org>
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--gvF4niNJ+uBMJnEh Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hello, On Sat, Jun 28, 2008 at 07:49:12AM +1000, Peter Jeremy wrote: > Yesterday, I planned to try an upgrade from 6.x to 7.x on one of the > servers at work, on the assumption that I could reasonably easily > revert to 6.x if things went bad. My confidence in being able to > do that was severely shaken when I saw "Upgrading metadata" messages > for both geom_mirror disks when the 7.x kernel booted. >=20 > Whilst I did not need to revert, some examination of the geom_mirror > source shows that (as I feared), a 6.x kernel will choke on a 7.x > geom_mirror. I didn't try now, but from my experience it should be fairly easy to=20 revert: Boot without gmirror from one the disks with the old kernel.=20 Have an old world available (CD, not yet installworld'ed) an write=20 gmirror label from single user mode with old metadata, add the other=20 disk and rebuild (more or less just go the way you go to setup a=20 bootable gmirror from an existing system). You would be in more trouble if you had some kind of real RAID format=20 (like a RAID 5 or something) on the disk, but gmirror is basically a set=20 of metadata whilst any single disk of the mirror is actually in a=20 format, that can be used without gmirror. I agree, that this is not actually straigt forward (as downgrading isn't=20 anyhow), but for the case "I see my 7.x kernel choking when upgrading=20 =66rom 6.x to 7.x" it should still be easy enough for an experienced=20 admin. Greetings, Oliver --=20 | Oliver Brandmueller | Offenbacher Str. 1 | Germany D-14197 Berlin | | Fon +49-172-3130856 | Fax +49-172-3145027 | WWW: http://the.addict.de/ | | Ich bin das Internet. Sowahr ich Gott helfe. | | Eine gewerbliche Nutzung aller enthaltenen Adressen ist nicht gestattet! | --gvF4niNJ+uBMJnEh Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.9 (FreeBSD) iEYEARECAAYFAkhl1EgACgkQiqtMdzjafymHmACgvd+e/GolQSBgj03FC42XY0p+ 2IoAnAs3MqOetiyELVP+kQ3pncRNwUaq =yrAY -----END PGP SIGNATURE----- --gvF4niNJ+uBMJnEh--
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