Re: Forcing kernel & root with bootloader

[Patrick Welche <prlw1%cam.ac.uk@localhost>]

On Tue, Jul 19, 2011 at 02:33:58AM -0500, Ben C. wrote:
> First of all, thanks for taking time to read my messgae.
> 
> I'm a bit new to the NetBSD bootloader.  I have a situation where I'm
> running the -current branch on 2x500GB disks that are setup in a RAID1
> configuration using RAIDframe as raid0.  It's marked as autoconfig and
> the "root partition":
> 
>    RAID Level: 1
>    Autoconfig: Yes
>    Root partition: Yes
>    Last configured as: raid0
> 
> Essentially, the datacenter the server is hosted at only offers a
> Linux rescue mode/bailout that can't read FFS partitions.  I'm wanting
> to keep a third 250GB disk as a rescue partition (and use the rest of
> the disk for scratch space for other things..)
> 
> I'd like to setup the third disk with the bootloader code and a very
> nice /boot.cfg so, in the event of bad things happening to the OS
> living on the RAID disks, I can ask the datacenter to boot from the
> 3rd 250GB disk and get a working system back up to recover from the
> failure.
> 
> Even when I tell the netbsd bootloader to, "boot hd2a:netbsd" it does
> indeed boot using the kernel located, but the kernel still insists on
> using the RAID disks since they are marked "root partition" (I
> assume).  I can get around this by using the -a "ask" flag but I'm
> hoping there is a way I can force it to boot wholly from hd2/wd2 in a
> non-interactive way.

There may be a nicer way, but I would simply pop

# Kernel root file system and dump configuration.
config          netbsd  root on wd2a type ffs

in the kernel configuration file hd2a:netbsd is built from. (Adjust to taste.)

Cheers,

Patrick