Problem with Installation on DELL Poweredge with Hardware RAID 1

Question

Hello Arch LInux community, 
I am a newbee with good linux knowledge of working on linux but not much of systems administration. I am very much interested to install Arch Linux on my new desktop which is a Dell poweredge having hardware RAID 1(PERC .... controller). It has windows 7 OS on its first partition.
I saw on the controller's BIOS menu that there are 2 1tb hard drives with something like --:--:00 and --:--:01 labels. And they were partitioned into two logical volumes which are visible once I boot into Arch linux live CD as, /dev/sda (about 250GB, and has windows OS on it) and /dev/sdb (about 700GB).
Firstly, I am confused with the hard disk labels: even though they are logical partitions (i.e: combined by RAID 1, they are seen as /dev/sda and /dev/sdb). In the arch linux Beginner's wiki, there is some description on configuring for RAID, which included mdadm or mdadm_udev module specification. I did include these modules, and followed the installatin instructions carefully. I was trying to install on /dev/sdb, with the following partitioning:
Sector map of partitions on /dev/sdb  : 1542848512 : 735.7 GiB
Disk identifier (GUID) : 967BF308-6E5E-43AD-AB2E-94EB975C3603
First usable sector = 34 Last usable sector  = 1542848478
Total  free space is 2023 sectors
Number        Start    End                  Size             Code    Name
                  34    2047                     FREE    
1               2048    2099199        1024.0 MiB    EF00            EFI System
2          2099200    2103295         2.0 MiB    EF02      BIOS boot partition
3          2103296    2615295         250.0 MiB    8300      Linux filesystem
4          2615296    212330495         100.0 GiB    8300     Linux filesystem
5       212330496    317188095      50.0 GiB    8300     Linux filesystem
6       317188096    1541924863    584.0 GiB    8300            Linux filesystem
     1541924864     1542848478                         FREE    
The instruction on the Beginner's wiki is somewhat difficult to understand for beginners. Especially I wasn't sure whether to make EFI System partition and BIOS boot partition or just EFI system partition. So I made both as per the instructions.
Is using UEFI compulsory, on UEFI based systems?
A little bit more sub-headings or division of instructions, in the Beginner's wiki,  based on the usage scenarios can be very beneficial for newbees like me.
I am finally getting the following error when I select the Arch Linux from the GRUB menu. Why it can't find the device?  I shall wait for your initial responses, and will give more specifics of my installation to find out any wrong step that I may have made.
[ 0.748399] megasas: INIT adapter done
ERROR: device 'UUID=40e603e9-7285-4ec8-8a06-a579358a52a0' not found. Skipping fsck
ERROR: Unable to find root device 'UUID=40e603e9-7285-4ec8-8a06-a579358a52a0' .
You are being dropped to a recovery shell
Type 'exit' to try and continue booting
Sh: can't access tty; job control turned off
[rootfs /]#

Answer 1

Well, you can see your RAID partitions and you're getting GRUB to load, and you are even being dropped to the recovery shell which means that the /boot partition is being found and is accessible. All vary, vary good things.
I would boot into the Arch live CD/USB again. Then check the UUID of the / Root partition. To do this I just check the log listing of /dev/disk/by-uuid
ls -l /dev/disk/by-uuid
Hopefully the UUID for the /root partition in the /boot/grub/grub.cfg is incorrect, and all you need to do is change it from 'UUID=40e603e9-7285-4ec8-8a06-a579358a52a0' to the correct UUID.
If the UUID is correct... then maybe the correct driver module is not complied into the initramfs. You could try adding that mdadm to the MODULES= list in /etc/mkinitcpio.conf then rebuild the initramfs again.
mkinitcpio -p linux
Hum..., the whole /dev/sda and /dev/sdb.... hum, You know... Maybe you need to change the line in /boot/grub/grub.cfg
set root='hd1,msdos1'
The hd1 is the equivalent to /dev/sda and the msdos1 is the equivalent of the First Partition i.e. /dev/sda1.. (note this is my disk yours may correctly have different numbers and not be a msdos partition)... owe wait... hum, you know I am fairly sure that like is really the root disk where the /boot partition is and has no relation to the / Root partition... Someone clear that up please.... It is hard for me to recall and I have my / Root parition encrypted, so It is hard for me to make heads or tails of that one right now, but that could be the problem too i.e. try changing hd1 to hd2 or hd0 or something.
Owe, and it may be faster if you just make temporary corrections to the GRUB menu by hitting the "e" key on the menu entry you want to change then hit.. I think F10 to boot the modified entry. That way you don't need to keep booting into the Live CD/USB
Last edited by hunterthomson (2012-09-20 05:52:33)