Re: GPT BIOS boot

[mlelstv%serpens.de@localhost (Michael van Elst)]

manu%netbsd.org@localhost (Emmanuel Dreyfus) writes:

>Hello

>I migrated a RAID setup from MBR to GPT and I have trouble getting
>it booting again, using legacy BIOS boot.

The bootloader looks for boot at
- the beginning of the boot partition
- the beginning of the boot partition + RF_PROTECTED_SECTORS
- the beginning of disklabel partition 'a' of type FS_RAID + RF_PROTECTED_SECTORS
  (the disklabel is taken from block 1 of the boot partition)

While the MBR can read the GPT and identifies the boot partition 
in the "outer" GPT, the PBR (bootxx) doesn't know how to handle
an 'inner' GPT. You could probably create a fake disklabel   
somehow.
 
UEFI boot would be much simpler since the bootloader is stored in
the EFI FAT filesystem outside the RAID, but AFAIK it doesn't know
about raidframe at all to load a kernel from the raid. But you can
tell it to load the kernel from the EFI partition instead by putting
a configuration into /EFI/NetBSD/boot.cfg.

N.B. I haven't actually tried this.

-- 
-- 
                                Michael van Elst
Internet: mlelstv%serpens.de@localhost
                                "A potential Snark may lurk in every tree."