Date: Thu, 07 Jun 2012 11:17:07 +0400 From: "Andrey V. Elsukov" <ae@FreeBSD.org> To: Hiroki Sato <hrs@FreeBSD.org> Cc: doc@FreeBSD.org Subject: Re: Handbook mirroring section Message-ID: <4FD05573.70801@FreeBSD.org> In-Reply-To: <20120606.200735.1551208261335301113.hrs@allbsd.org> References: <alpine.BSF.2.00.1206052220390.10777@wonkity.com> <20120606.185023.497714372668376681.hrs@allbsd.org> <4FCF3021.5070802@FreeBSD.org> <20120606.200735.1551208261335301113.hrs@allbsd.org>
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This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig611EC6E34233A72122041D46 Content-Type: text/plain; charset=KOI8-R Content-Transfer-Encoding: quoted-printable On 06.06.2012 15:07, Hiroki Sato wrote: > ae> 1. When geom_mirror module is not loaded GEOM_PART will complain th= at the > ae> backup GPT header is not in the last LBA and partition table will b= e marked > ae> as CORRUPT. The recover operation will destroy the GEOM_MIRROR's me= tadata. > ae> > ae> 2. If primary GPT header or table become damaged, then gptboot will= not > ae> detect GPT because the backup GPT header is not in the last LBA. So= , the > ae> system will not boot. >=20 > Thanks, I see. Do you think the attached patch is too aggressive for > the problem 2? The value of altlba should be matched with one in the > original secondary header when the primary header is corrupted and > the secondary header is looked up in this way. Yes, i also have thought about this and this should work for most GEOM cl= asses, but i revised again PMBR code and it seems that it will not work anyway := ) Our PMBR doesn't use backup GPT header and table, and it doesn't verify correctness of primary GPT. =46rom the other side, there are three situations when we use GPT: 1. FreeBSD is only one system on the disk and we use PMBR and gptboot to = boot it. In case if we will fix PMBR your patch will help. 2. FreeBSD is no one on the disk, but we still use legacy boot method (PM= BR+gptboot). I don't know what behavior have other systems when they detect invalid GP= T (i.e. when backup header is not in the last LBA). 3. We use UEFI (it is not work yet). Also i don't know what UEFI firmware will do with invalid GPT. --=20 WBR, Andrey V. Elsukov --------------enig611EC6E34233A72122041D46 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (MingW32) iQEcBAEBAgAGBQJP0FV4AAoJEAHF6gQQyKF6R4AH+QGGVcGAu/oVRT/slQtxIi1V 07BSJ+a5YRvbLYonysH807SySjycy76aLM2WO5zMR03NYUH9Wz4sFn0XbXZdr7Sh 7LBPVuvl/8P6tKOuprbMUywXKggjIHKIJ5QQNDwEc43HTLaQ6N/ZeTHpdPFJJqs7 rZpDguH0PG07vV518JFKO5NudKblUv0j81auNFs2vJtv1cT/Y6DOSXKwH98R7L2M udEcNdchzvVTspE8LJvMFuvg+7x58eJlCJpyvpKtHxdLr6tRDfazdNaw/y7XgPnQ 2Y+o2tZx33CXi8WnOSwNBaOVnjkKfsoJs6097gj6ecNulezKuJvUHlRehSuT+9k= =Rx8+ -----END PGP SIGNATURE----- --------------enig611EC6E34233A72122041D46--
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