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Comments: In-reply-to John Baldwin <jhb@freebsd.org>
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Date: Thu, 16 Aug 2012 10:06:46 +0300
From: Daniel Braniss <danny@cs.huji.ac.il>
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Cc: Garrett Cooper <yanegomi@gmail.com>, freebsd-hackers@freebsd.org
Subject: Re: GPT boot from 2nd. disk fails
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> On Wednesday, August 15, 2012 4:46:28 am Garrett Cooper wrote:
> > On Wed, Aug 15, 2012 at 1:27 AM, Daniel Braniss <danny@cs.huji.ac.il> wrote:
> > > hi,
> > > this host has to disks:
> > > sa0> gpart show
> > > =>       34  976773101  ada0  GPT  (465G)
> > >          34        128     1  freebsd-boot  (64k)
> > >         162    4194304     2  freebsd-ufs  (2.0G)
> > >     4194466   33554432     3  freebsd-swap  (16G)
> > >    37748898  939024237     4  freebsd-zfs  (447G)
> > >
> > > =>       34  976773101  ada1  GPT  (465G)
> > >          34        128     1  freebsd-boot  (64k)
> > >         162    4194304     2  freebsd-ufs  [bootme]  (2.0G)
> > >     4194466    8388608     3  freebsd-swap  (4.0G)
> > >    12583074  964190061     4  freebsd-zfs  (459G)
> > >
> > > but no amount of magic will cause boot from the second disk, it will 
> always
> > > boot from the first disk.
> > >
> > > any insights?
> > 
> >     Use boot0cfg -s 5 (untested with GPT disks)?
> 
> Will not work with GPT disks.  They use /boot/pmbr to boot, not /boot/boot0.
> 
> If you can get your BIOS to explicitly boot ada1 from the start via a BIOS
> setting, that should work.  Another option would be to break into gptboot's
> prompt (similar to breaking into boot2) aud typing in 'ad1p2:/boot/loader' or 
> some such.  If that works you should even be able to write that to 
> /boot.config on ada0p2's filesystem.

sorry, as usual my questions are a bit terse :-),
I want to switch between roots either at boot time (this is very tricky now,
since breaking into boot2 needs very fast fingers) or before reboot.
btw, it's 1:ad(0p2)/boot/loader
also, since the disks are hot swap, i can switch between them, but I realy
want to do it via software!

the bootme trick did work, on a different host/setup and sometime ago.

before GPT, when we had MBR, I could switch between slices/partitions either
via the menu or via boot0cfg, so maybe I should go back to mbr.

Cheers,
	danny