will hde be hd1 in grub.conf?

[Paul Howarth]

On Fri, 2006-03-24 at 23:33 -0500, Jack Howarth wrote:
>      One other question. I am unclear on the following issue. If you have
> two drives with the grub setup being on the first drive (hda)  and with a
> a grub.conf on the first drive starting with...
> 
> fallback 1
> 
> title Fedora Core (2.6.16-1.2069_FC5smp) boot from hda using md2
>         root (hd0,0)
>         kernel /vmlinuz-2.6.16-1.2069_FC5smp ro root=/dev/md2 rhgb quiet
>         initrd /initrd-2.6.16-1.2069_FC5smp.img
> title Fedora Core (2.6.16-1.2069_FC5smp) boot from hde using md2
>         root (hd1,0)
>         kernel /vmlinuz-2.6.16-1.2069_FC5smp ro root=/dev/md2 rhgb quiet
>         initrd /initrd-2.6.16-1.2069_FC5smp.img
> 
> ...does the 'root (hd0,0)' in the first grub entry just provide grub
> with the drive to get the /boot directory from? Or does it also tell
> any additional commands where to get things like /dev/md2 from?
>      I ask because I am trying to boot a machine with normal partitions
> (and their usage in /etc/fstab) on the first (hda) drive and md partitions
> (copied with tar from the first drive) on the second drive. The RAID1
> conversion protocols I have seen suggested that I could use the above
> grub entries to have the grub installed on the first drive boot the md
> partitions on the second. However it appears that the fallback may not
> have occured. I am wondering if for md partitions, the 'root (hd0,0)'
> might confuse the boot process with the md partitions being looked for
> off of the same drive (hda) that the /boot parition was gotten from.
> That part of the RAID1 conversion writeup was unclear.

Grub doesn't understand RAID partitions. It can be made to work with
RAID1 mirror partitions though, by treating them as regular partitions.
It just reads the data from one of the disks and wouldn't try the other
part of the mirror in the event of an error.

The root (hd0,0) does indeed tell grub where to find the /boot directory
where the kernels and initrd live. And that's all.

Paul.