centos 6.5 - RAID 1

partition first disk and select type fd - linux raid autodetect
	fdisk /dev/sdb

detect new partition
	partprobe /dev/sdb

partition second disk and select type fd - linux raid autodetect
	fdisk /dev/sdc

detect new partition
	partprobe /dev/sdc

create raid 1
	mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sdb1 /dev/sdc1

watch the raid build progress
	watch cat /proc/mdstat

format new raid disk
	mkfs.ext4 /dev/md0

Your system doesn't automatically remember all the component partitions of your RAID set. This information has to be kept in the mdadm.conf
	mdadm --detail --scan > /etc/mdadm.conf
(for ubuntu mdadm --detail --scan > /etc/mdadm/mdadm.conf)

mount raid1 disk
	mkdir /mnt/raid
	mount /dev/md0 /mnt/raid/
	df -H /mnt/raid/

add in fstab
	nano /etc/fstab
-------------------------------------------------------------------
/dev/md0	/mnt/raid	ext4	defaults	1 2
--------------------------------------------------------------------

mount all the devices in the /etc/fstab file that have automounting enabled (default) and that are also not already mounted.
	mount -a


to get detailed info about the raid
	mdadm --query --detail  /dev/md0