[CentOS] MIrrored drives won't boot after installation

Tue Apr 26 10:12:17 UTC 2005
Jamie McKnight <warthog at warthogsolutions.com>

On Mon, 2005-04-25 at 22:25 -0400, Chris Mason wrote:
> > When you configure the drives as RAID1 the installer never request where
> > to install the boot record. If configuring with one drive (no raid) the
> > installer will ask where to install the record.
> > 
> > Gerald
> 
> So how do I fix this? I really need to get a mirrored drive system up and
> running.
> 
> Chris Mason
> US Number: (646)722-0001 US Fax (815)301-9759
> Skype: netconcepts
>  

This is what I did to get it working on a firewall I built recently.

After install, leave the cd or dvd in and at the boot prompt type:

linux rescue

Once it gets into rescue mode, you can chroot /mnt/sysimage (I believe
is where it mounts your OS, read the prompts while rescue mode is
starting and it will tell you what your chroot argument should be as
well)

Now create a file with the following contents (NOTE: the below output
assumes that / and /boot are on the same drive, your contents will be
different depending on the drives used and the partitioning)

root (hd0,0)
install /boot/grub/stage1 d (hd0) /boot/grub/stage2 0x8000 \
hd0,0)/boot/grub/menu.lst
quit

If the formatting does not come through, that should be 3 lines.

Then you run the command:

grub --batch --device-map=/boot/grub/device.map < tmp.file

That did it for me.  Some things to note, This only writes the grub data
to the first drive.  If /boot is it's own partition, the paths in the
file will not include /boot.

Hope this helps.

Jamie