Install Arch Linux on Raid0 with GPT and Grub 2

Install Arch Linux on Raid0 with GPT and Grub 2

First start by downloading the iso.
dd it onto usb stick 
boot iso

then start by setting up internet connection
test it : ping www.google.com


Load the appropriate RAID (e.g. raid0, raid1, raid5, raid6, raid10) modules. 
We will use raid0, and raid1
modprobe raid0
modprobe raid1

Prepare Hard Drives
Each drive will have 100Mb for /boot these will be in raid1 for safety
The / partition takes the remainder of the drive

install gdisk for formatting in GPT
pacman-db-upgrade
pacman -Syy
pacman -S gptfdisk

gdisk /dev/sda

1. Add a new partition: n
2. Select the default partition number: Enter
3. Use the default for the first sector: Enter
4. For sda1 type the appropriate size in MB (i.e. +100MB and +2048M). 
5. Select BIOS BOOT PARTITION as the partition type: ef02  !!!very important
6. Write the table to disk and exit: w

Repeat for the second partition on /dev/sda but for step 4 just press ENTER to use the remainder of the disk.

Now create the raid's with mdadm

mdadm --create /dev/md0 --level=0 --raid-devices=2 /dev/sd[ab]2

mdadm --create /dev/md1 --level=1 --raid-devices=2 /dev/sd[ab]1

ok than we mount our partition

mount /dev/md0 /mnt

mkdir /mnt/boot 

mount /dev/md1 /mnt/boot 

pacstrap /mnt base

genfstab -U /mnt >> /mnt/etc/fstab

arch-chroot 

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

EDIT : mkinitcpio.conf

1.Add the mdadm_udev  hooks to the HOOKS list in /etc/mkinitcpio.conf after udev.

mkinitcpio -p linux

INSTALL BOOTLOADER GRUB 2

pacman -S grub

grub-install --target=i386-pc --recheck /dev/sda

grub-mkconfig -o /boot/grub/grub.cfg

And you are done, you can reboot