Date: Sat, 18 Feb 2012 23:09:06 -0800 From: Freddie Cash <fjwcash@gmail.com> To: Kevin Oberman <kob6558@gmail.com> Cc: wblock@wonkity.com, freebsd-stable@freebsd.org, 000.fbsd@quip.cz, Andriy Gapon <avg@freebsd.org>, mandrews@bit0.com, freebsd@jdc.parodius.com Subject: Re: New BSD Installer Message-ID: <CAOjFWZ7PaUChZm7_Mn00DNNQuwp5o5=SNP6W03JyjWS=sHFyQw@mail.gmail.com> In-Reply-To: <CAN6yY1skQ=eO39vvbE-mLFKZb5TxXJJqtWydZOQpVBsiZpBHYw@mail.gmail.com> References: <CAOjFWZ5EhGFr_Vp0%2BTRfxvgm6KZxv9QO3UfVdKurA96z3axDMQ@mail.gmail.com> <20120217.160430.406937514120319292.hrs@allbsd.org> <4F3E3000.9000206@FreeBSD.org> <20120217.232843.2212672671663755444.hrs@allbsd.org> <4F3EC8DD.6040500@FreeBSD.org> <CAOjFWZ5Jm9M27J=%2B2jj5b4mSyE_i1Jq2YyXBKs%2BPabrUQyiYhg@mail.gmail.com> <CAN6yY1skQ=eO39vvbE-mLFKZb5TxXJJqtWydZOQpVBsiZpBHYw@mail.gmail.com>
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If you're mirroring the disk with gmirror, how are you dual-booting the disk? This discussion is about using gmirror to mirror two entire disks, and then use GPT to partition the mirror device. Dual-booting has no bearing on that, as gmirror is a FreeBSD-only technology. Cheers, Freddie Cash fjwcash@gmail.com On Feb 18, 2012 10:37 PM, "Kevin Oberman" <kob6558@gmail.com> wrote: > On Fri, Feb 17, 2012 at 1:50 PM, Freddie Cash <fjwcash@gmail.com> wrote: > > On Fri, Feb 17, 2012 at 1:38 PM, Andriy Gapon <avg@freebsd.org> wrote: > >> And just in case: > >> Unified Extensible Firmware Interface Specification Version 2.3.1, > Errata A > >> September 7, 2011 says: > >> [snip] > >>> Two GPT Header structures are stored on the device: the primary and the > >>> backup. The primary GPT Header must be located in LBA 1 (i.e., the > second > >>> logical block), and the backup GPT Header must be located in the last > LBA > >>> of the device. > >> > >> I can not see any ambiguity or openness to interpretation in this > paragraph. > > > > Unless it's specified somewhere else (which is possible), in this > > paragraph, "device" does not necessarily mean "physical disk". "Last > > LBA of the device" could be interpreted as "last LBA of the GEOM > > provider". > > > > The beauty of GEOM is that "device" is whatever logical mapping it > provides. > > > > After all, LBAs are logical addresses (it's right there in the name!), > > not hardwired physical sector addresses. ;) If they were hardwired, > > then how would internal sector remapping work? ;) > > Please remember that some disks are dual-boot. FreeBSD may understand > geom has the backup one block from the last LBA on the disk, but no > other OS is likely to do so. > > Unless I am missing something, this should be a non-starter. Totally > unacceptable. The backup belongs in the last and only in the last LBA > on the physical disk. > -- > R. Kevin Oberman, Network Engineer > E-mail: kob6558@gmail.com >
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