Re: gptmbr.bin vs RAIDframe

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

    Date:        Wed, 17 Jun 2015 12:01:10 +0100 (BST)
    From:        Stephen Borrill <netbsd%precedence.co.uk@localhost>
    Message-ID:  <Pine.NEB.4.64.1506171043190.534%ugly.internal.precedence.co.uk@localhost>

  | dk -> raid -> dk doesn't allow you to set -A root on the RAID
  | (well it sets it, but it doesn't work),

Can you tell me what you believe doesn't work exactly?   I do that, and
it seems to work just fine for me.

I do use your #1 method for booting (separate non-raid boot wedge  - or
if you like, manual raid1 ... that is, each drive has a wedge containing
a root filesys, including all the boot stuff, that are kept synchronised
manually .. the only thing that ever changes on them is /netbsd and that
changes very rarely for me.  Those filesystems are not normally mounted.)

But beyond that, I have a large wedge (on each drive) that contains
a raid1 (mirrors), and in that, a GPT with wedges, one of which is root.
The raid is "-A root" and it works just fine.

  | so there's still a missing piece of the puzzle.

You do need to know that the root wedge needs to be called "raidNa"
(in my case, "raid7a" as it is raid7 that contains the root).

  | Yes, you need to know the device name for root in your fstab,

fstab contains ...

NAME=raid7a             /               ffs     rw,log           1 1
tmpfs                   /tmp            tmpfs   rw,-m=1777,-s=537255936
NAME=SWAP_0             none            swap    sw,dp            0 0
NAME=USR_7              /usr            ffs     ro               1 2
(etc).

  | perhaps the name 
  | lookup code could learn to recognise %ROOT% or such like to mean
  | /dev/<kern.root_device><'a'+kern.root_partition>

disklabels are dying, adding more hacks to deal with them seems
counter-productive.  kern.root_partition is a disklabel artifact, it
makes no sense when using wedges.

For booting, what we need in the fullness of time, is proper UEFI boot code,
rather than a legacy style MBR boot half-block and the tiny boot loader that
it can handle.

kre