grub failure to update MBR (using RAID and LVM)

[Paul Howarth]

Paul Pianta wrote:
> On Thu, 2005-02-17 at 18:32 -0500, Shawn Iverson wrote:
> 
>>Great, thanks! 
> 
> 
> no worries :)
> 
> 
>>Also, I performed a series of simulated failures and would like to offer advice below on setting up RAID for use with GRUB for anyone interested:
>>
>>1) Set your BIOS to attempt to boot all drives before giving up
>>2) Make a separate entry in your grub.conf for each drive in the mirror, so that when one fails, you can fall back to the good drive by selecting it on the menu.  For example:
>>
>>default=0
>>timeout=10
>>#splashimage=(hd0,0)/grub/splash.xpm.gz
>>title Fedora Core Primary (2.6.10-1.766_FC3)
>>        root (hd0,0)
>>        kernel /vmlinuz-2.6.10-1.766_FC3 ro root=/dev/Volume00/root
>>        initrd /initrd-2.6.10-1.766_FC3.img
>>title Fedora Core Secondary (2.6.10-1.766_FC3)
>>        root (hd1,0)
>>        kernel /vmlinuz-2.6.10-1.766_FC3 ro root=/dev/Volume00/root
>>        initrd /initrd-2.6.10-1.766_FC3.img
> 
> 
> I thought specifying the device to grub when you run grub-install took
> care of setting up the right 'root' device for that drive if it is ever
> booted from - maybe not though?
> 
>>3) Notice that I commented out the pretty splash image.  If hd0 fails, where will the spash image come from?
> 
> 
> Wouldn't the pretty splash image be mirrored in the /boot/grub/
> directory of your second drive?

Grub is working from the individual drives; it doesn't see the "mirror". 
So "splashimage=(hd0,0)/grub/splash.xpm.gz" means "get the splash image 
from the first drive", which won't work if the first drive is broken.

Paul.