====== 2 x 3TB + GPT + Grub2 + RAID + LVM + ENCRYPTION ======

The idea is to have two harddrives in mirror mode with complete system encryption.
For each harddrive we need a BIOS boot partition with grub core.img stuff in them. They have to be configured and installed (in grub) in such a way that each harddrive can boot from itself.
I have decided to have the swap partitions not in any RAID configuration. Each harddrive will have a separated swap partition, each swap will be encrypted with a random key. 
The rest of the disk is the whole linux system (including /boot). This is going to be a RAID1 (copy) with a LVM on top (to allow future extension) and encryption on top.

In each harddrive do the following:

  * Create GPT partition table with gdisk. (Check that the alignment is to 2048-sectors for 4Kb harddrives, if not set it like that)
  * Create a BIOS boot partition of 1MB (necessary for grub2 on GPT disks)
  * Create a Linux swap partition (2G)
  * Create a Linux RAID partition (the rest of space)

Now in the first harddrive do:

  * Create the Linux RAID1 device:

  mdadm --create md0 --level=1 --raid-devices=2 -R /dev/sdf3 missing

  * Replace "missing" for your second drive if its already connected.

  * For some reason the drive is read only still:

  md0 : active (auto-read-only) raid1 sdf3[0]
        ?????? blocks super 1.2 [2/1] [U_]

  * Make it read/write

  mdadm --readwrite /dev/md/md0 
  
  * Update /etc/mdadm/mdadm.conf

  mdadm --examine --scan >> /etc/mdadm/mdadm.conf

  * Create an LVM2 logical block device on top of this RAID:

  pvcreate /dev/md/md0
  vgcreate test /dev/md/md0
  lvcreate -l 100%VG -n root test

  * Create a dm-crypt on top of the LVM:

  modprobe sha512_generic
  modprobe aes_generic
  modprobe aes-x86_64
  cryptsetup -y luksFormat /dev/test/root -c aes-xts-plain64 -s 512

  * Activate dm-crypt:

  cryptsetup luksOpen /dev/mapper/test-root test-root_crypt

  * Create ext4 partition:

  mkfs.ext4 /dev/mapper/test-root_crypt


In this moment the disk is ready for installing software on it. What I'm trying to do is to copy my old harddrive installation into this new system. I will probably copy this using rsync, but first I want to check if the ext4 filesystem can be seen by grub2. I plan to test this from the grub console on my currently running system.

===== Important commands =====

blkid - lists uuids of block devices, could be useful for configuring grub.
grub-mkdevicemap - could be necessary if you add more harddrives and want to install grub in the new harddrives.