On Thu, Oct 18, 2001 at 12:14:16PM +1000, Luke Mewburn wrote:
> On Wed, Oct 17, 2001 at 06:45:13PM -0400, Lalor, Chris wrote:
> > As per Luke's changes committed 20001030, the -current bootblocks have
> > support for booting off of a RAID1 mirror. The commit also mentions that
> > installboot(8) does not yet have support for installing bootblocks to
> > such a mirror. Has this support been added (as I see no such
> > announcements) or is there a way to get around this and install the
> > bootblock in some other manor?
> 
> installboot(8) hasn't been hacked to install the first stage booter
> on the underlying physical component and the second stage boot
> (/boot) on the raidXa device; I took a look at this and solving
> this is non trivial and ugly.
> 
> My workaround was to create a small 4.2BSD partition near the physical
> start of the disk on the underlying device (e.g, `wd0h', starting at
> offset 63), installboot to wd0h, have the kernel on raid0a (disklabel
> type `4.2BSD') which is composed of wd0a/wd1a (disklabel type `RAID'),
> and use raid autoconfig. The boot sequence is:
> 
> 	- The MBR bootblock in MBR executes the bootblock in
> 	  NetBSD 0xA9 partition
> 
> 	- The first stage NetBSD bootblock then loads /boot from
> 	  hard-coded sectors (which happen to be physically located
> 	  in wd0h)
> 
> 	- /boot - the second stage bootblock - searchs for the kernel
> 	  off the boot device and loads it.  I can't recall if I
> 	  had to put a kernel in wd0h or if /boot assumes the kernel
> 	  is on the first partition of the boot device and therefore
> 	  uses wd0a; it's been nearly 12 months since I used this
> 	  setup (I now use hardware raid cards). `Suck it and see'.

It always tries to load from the first partition (wd0a) unless told
otherwise on the command line. Since 1.5.1 the boot loader is able
to load a kernel from a 4.2BSD type partition, or a RAID type
partition (provided it's a raid-1 and the kernel is on the first partition
of this raid).
So you only need /boot in wd0h; the kernel can be on raid0a.

--
Manuel Bouyer, LIP6, Universite Paris VI.           Manuel.Bouyer@lip6.fr
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