Grub and software RAID

[Nigel Jewell]

Hi all,

I have a problem regarding grub and a linux software RAID setup.

Basically, the deal is this.

I installed Redhat 7.2 on two 20Gb harddrives.  As I was setting it up I 
mirrored the disks using software RAID 1.  The disks were setup as:

/hda1 and /hdc1 = /boot (around 43Mb)
/hda2 and /hdc2 = swap  (around 512Mb)
/hda3 and /hdc3 = /     (the rest)

Redhat's setup installed grub on the first disk (hda) okay.  The system 
boots and the RAID works fine.  If I unplug the second disk (hdc) it 
still boots fine and the software RAID is still happy (but one disk 
less).  But if I unplug the first disk (hda) and leave hdc plugged in it 
doesn't boot.

This led me to the conclusion that grub wasn't setup on the second 
harddisk (hdc).  So I reconnected both of the disks and sync'd them. 
Boot grub and did:

root (hd1, 0)
find /grub/stage2
setup (hd1)

and it seems to work.  However, it still does not boot with only hdc 
connected.  I get the error "GRUB Hard Disk Error" (or something similar).

Is the problem that I need to have the second disk as hd0 when 
installing grub so that grub knows what to do with only one disk when 
hda is disconnected?

I presume the easiest way is to do this from floppy?

Any other ideas?

Nige.

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