[GLLUG] RAID1 and Debian 7.2.0 installer

[John Edwards]

BOn Mon, Oct 14, 2013 at 10:24:29AM +0000, Chris Bell wrote:
> Hello,
>    I have been trying to install Debian 7.2.0 to a Pentium 4 32-bit box with
> a pair of 3TB discs configured with all RAID1 partitions.

The first thing to check is whether a machine that old can detect the
3TB disks correctly. Then check whether the 3TB disks are partitioned
using the DOS style partitions or the newer GPT partitions.

Also I assume that the machine can not boot using EFI and so uses a
conventional PC BIOS.


> I believe that GRUB2 can boot from / installed to a RAID1 partition,
> but I have not been able to make any partition bootable.

GRUB2 can boot from a RAID1 mirror (also RAID5 and LVM).

I'm less certain about whether it can boot from a pure GPT setup.
The GRUB manual is less than helpful here:
  https://www.gnu.org/software/grub/manual/html_node/index.html

Although there is some reference to using 'bios_grub' or 'gptsync' on
GPT partitions:
  https://www.gnu.org/software/grub/manual/html_node/BIOS-installation.html#BIOS-installation
  https://www.gnu.org/software/grub/manual/html_node/gptsync.html#gptsync

And some other pages found via Google that might be useful:
  http://www.wensley.org.uk/gpt
  https://wiki.archlinux.org/index.php/GPT#Bootloader_Support


> There is a line included in the raid
> set-up to enable booting which does not appear to do anything except make
> the screen flash.

What do you mean? I've never seen such a line needed in the mdadm.conf
(Linux software RAID configuration file). I would have thought that
the choice of which partition to boot from would be purely the
decision of the boot loader GRUB.


> What do I need to do? Should I just try to cofigure the
> RAID using an alternative installer? Should I insert an old IDE PATA disc
> just to run GRUB2 from a bootable minimal installation? Thanks.
> 
> Bootable Partition 1 66GB RAID1 / 
> Bootable Partition 2 66GB RAID1 unused, for future use as alternate / 
> Bootable Partition 3 66GB RAID1 unused, for future use as alternate / 
>          Partition 4 16GB RAID1 swap
>          Partition 5 rest RAID1 /serv


Does booting a Debian CD is rescue mode help in booting the system, or
at least get some data about the disks and partition layout?

The output of 'parted /dev/sda print' (as root or sudo) will give
full details of the partitions and which type they are.



-- 
#---------------------------------------------------------#
|    John Edwards   Email: john at cornerstonelinux.co.uk    |
#---------------------------------------------------------#
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