# apt-get install mdadm
# apt-get install lvm2

Check existing arrays:
# cat /proc/mdstat

Create RAID 5 array:
# mdadm –create –verbose /dev/md0 –level=5 –raid-devices=3 /dev/sdb /dev/sdc /dev/sde

Check the array exists:
# cat /proc/mdstat
# mdadm –detail /dev/md0
=⇒ there is an initial phase of reconstruction when an array is created. It is supposedly functional during this time.

Make the array a LVM Physical Volume (so it can be used by LVM):
# pvcreate /dev/md0
=⇒ That takes time!

Check result:
# pvs
# pvdisplay

Define a LVM Volume Group consisting of the array (usually on several disks, but we already packed them with RAID so it's just one 'drive'):
# vgcreate vg_data /dev/md0
=⇒ takes time as well!

Check result:
# vgdisplay vg_data