Re: booting from wd0b / raidframe

[David Laight <david%l8s.co.uk@localhost>]

On Wed, Dec 09, 2009 at 10:15:10PM +0100, Manuel Bouyer wrote:
> On Wed, Dec 09, 2009 at 03:44:50PM +0000, Patrick Welche wrote:
> > I seem to be getting rusty, and can't work out how to make a raidframe
> > mirror boot(!)
> > 
> > dd | hexdump confirms that sector 0 contains /usr/mdec/mbr
> > I recognise the beginning of /usr/mdec/bootxx_ffsv1 from sector 63
> > 
> > The mess might because I have swap starting in sector 63 - is that not
> > legal?
> 
> I don't think so. I suspect bootxx_ffsv1 will look at the beggining
> of the NetBSD partition for a valid filesystem, it doesn't read the disklabel.

Look at sys/arch/i386/stand/bootxx/boot1.c, rules foe finding /boot are:

1) Try for a filesystem at the start of the 'type 169' partition
2) Add 64 sectors and try again
3) Look at disklabel (2nd sector of ptn) info for 'a'
3a) If 'a' is FS_RAID, add 64 sectors
3b) look for fs.

Once an fs is located (probbaly looking for magic numbers) then try
to open /boot itself.

        David

-- 
David Laight: david%l8s.co.uk@localhost