setup-storage and grub issue

[Christopher Huhn]

Michael Tautschnig wrote:
>> I started playing around with setup-storage to setup a
>> lvm-on-raid1-2disk box. setup-storage really works out fine, but grub
>> installation fails, apparently because the $BOOT_DEVICE is set nowhere.
>> disk_var.sh only defines $SWAP_LIST and $ROOT_PARTITION
>>     
> Hmm, yes, $BOOT_* only get defined in case they reside on a normal partition. I
> think I can easily fix this if you can give me a hint what they should be set to
> in this case. Ok, $BOOT_PARTITION is obvious, but what should $BOOT_DEVICE be
> set to? I'm lacking the knowledge about RAID&grub, apparently. Could you help me
> out?
>   
I haven't figured out the proper method yet.
Anyhow installing grub in the MBR of disk1 is sufficient to boot the
installed system.
So in my case BOOT_DEVICE should be /dev/sda.

But to boot in case of a failure of the primary disk, grub has to be
installed to the MBR of disk2 also. Obviously this will only work for
RAID1. Additionally some howtos suggest a kind of device swap magic to
make grub think that disk2 is disk1 on install.

Also menu.lst needs to be modified to contain a fallback entry that
boots from disk2. This will have to be updated by hand on every kernel
upgrade - unless update-grub will be patched to handle such RAID setups.

Finally mdadm has to be on the package list for the installed system.
Then the created initramfs will happily boot from the RAID1 rootfs
without further intervention. This should probably be mentioned in the wiki.

Kind regards,
    Christopher

-- 
Christopher Huhn
Linux therapist
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