Re: Grub and software RAID

[Gerard W. Patterson]

On Mon, Mar 11, 2002 at 10:56:03AM +0000, Nigel Jewell wrote:
> 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.
> 
> -- 
> URL: http://www.pixexcel.co.uk
> 
> 
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I run a very similar configuration.  What I do is (using a grub floppy)
remove the first disk and install the grub boot-loader on the second disk
with the same configuration as the first one (since the second disk is now
the first and only disk).  This works for me, anyways...

Regards,

  Gerry
-- 
Gerard W. Patterson, B.Sc           |   Computalog Wireline Services
Software Engineering                |   Precision Drilling TSG, Inc.
<address@hidden>    |