ZFS root partition

[John Baldwin]

On Wednesday, July 28, 2010 5:02:57 pm Marius Strobl wrote:
> 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? :)

dfr@ has C bits to handle ZFS reading for the loader that should be easy to
reuse.  The only MD bits are that you need to probe all the available
drives so ZFS can discover all the devices that back volumes / pools.

-- 
John Baldwin