Re: grub2 on power6 box.

[Lennart Sorensen]

On Fri, Jul 23, 2010 at 09:57:37AM -0400, Lennart Sorensen wrote:
> On Fri, Jul 23, 2010 at 07:56:27AM +0200, Vladimir 'φ-coder/phcoder' 
> Serbinenko wrote:
> > On 07/22/2010 11:23 PM, Lennart Sorensen wrote:
> > > I am trying to use grub2 to boot an IBM p520 power6 box.  I know yaboot
> > > can do the job, but it doesn't deal with software raid, ext4, LVM or
> > > anything else useful.
> > >
> > > I have managed to get as far as booting to a grub prompt from disk.
> > > Unfortunately it doesn't appear to be seeing any disks at that point.
> > >
> > > The way I got it this far was to create an 8MB (smallest cfdisk would
> > > make) PReP boot partition, and then run grub-mkimage -n -o /tmp/grub -O
> > > powerpc-ieee1275 *.mod in the ieee1275 grub directory.  I then dd'd
> > > /tmp/grub to /dev/sda1 (the PReP boot partition).
> > >
> > >   
> > You need to add -p "<your /boot/grub in grub notation>". Also avoid the
> > raid and lvm-related modules you don't need. OFW exposes ghost devices
> > so assembling raids which involves looking at all devices is slow
> 
> I will try that (although I think I did).
> 
> I can't even get it to do ls on any disk or anything.  It really seems
> to be behaving as if it doesn't detect any disks.

So I fixed ofpathname (it was not working because it did find /sys -name
$device, which mathes multiple things on modern kernels).  I changed the
find to find /sys -type d -name $device and now that works.  So now I
can run grub-install, but of course that just creates a /boot/grub/grub
file with the main grub and a filesystem module attached.  It doesn't
actually boot.

It set the
boot_device=/address@hidden/pci1014,address@hidden/sas/address@hidden:4,\grub

/dev/sda4 is a fat16 partition mounted as /boot/grub.  Unfortunately I
am not convinced the IBM boxes know how to read filesystems or boot
files.  It seems it only wants to read raw from a PReP boot partition.
So when I dd /boot/grub/grub to /dev/sda1 (an 8MB PReP boot partition)
the system does start grub, but of course since grub was only the core
plus the fat module, it just says:

Welcome to GRUB!                                                                
                                                                                
                                                                                
                               
                                                                                
                                                                                
                                                                                
                               
error: no device is set.
Entering rescue mode...                                                         
                                                                                
                                                                                
                               
grub rescue>

So what do I do then to get it to know what device to use?

-- 
Len Sorensen