ZFS root partition

[Marius Strobl]

On Tue, Jul 27, 2010 at 09:45:31AM -0400, John Baldwin wrote:
> On Tuesday, July 27, 2010 4:40:48 am Rob Farmer wrote:
> > Is is possible to have a ZFS root with sparc64? I've used one of the
> > guides on the wiki, http://wiki.freebsd.org/RootOnZFS/GPTZFSBoot, on
> > amd64 and it worked fine, but that doesn't seem to apply, since the
> > /boot/pmbr and /boot/gptzfsboot files don't exist on sparc64.
> 
> Booting from a GPT isn't supported for OpenFirmware, so it doesn't work for 
> sparc64.
> 

Looking at the description of the ZFS on-disk format it should
be possible to implement something similar with the VTOC scheme
though; the first-stage loader (8K max., we have no zero-stage
on sparc64) probably should jump to something like a 1.5-stage
loader located in the 3.5MB boot block area located after the 
ZFS uberblock and would need to know how to read ZFS in order
to finally load /boot/loader. I haven't looked at how the GPT
variant works in detail but I suspect most of the ZFS-specific
actually could be recycled. The other missing part would be to
teach some part (maybe GEOM_PART) how to write something to the
ZFS boot block area. Any takers? :)

Marius