Re: overriding RAIDframe disks as root disks with multiboot

[Robert Elz <kre%munnari.OZ.AU@localhost>]

    Date:        Wed, 11 Nov 2009 14:03:58 -0600
    From:        David Young <dyoung%pobox.com@localhost>
    Message-ID:  <20091111200358.GP603%ojctech.com@localhost>

  | What am I missing?

Most probably that the MD root finding code just looks for the
drive from which the system booted - last I heard, none of NetBSD's
ports could boot from a (raidframe) raid0 or raid5 - if you want
root to be on one of those then (other than specifying rootdev in the
kernel build) you're stuffed...

That code (I believe) imlements the "ratdctl -A root" functionality,
that marks a raid "device" as a candidate root device - when the kernel
isn't configured for a specific root, the raid filesys is selected.

FWIW, I think the code to allow the user to override that at boot
time would be a useful addition - while it is possible to boot,
"raidctl -A yes" or "raidctl -A no", and then reboot, or perhaps
"boot -a" on systems that support that, but that's a painful
sequence of operations for what should be a simple task.

It should always be
        1. what the user explicitly asks for
        2. what the kernel has built in
        3. hacks like "ratdctl -A root" (or perhaps similar things for cgd etc)
        4. where I think I came from

in that order to find the root device.

kre