fdisk /dev/xvda
n (create new partition – use defaults)
p (primary partition)
3 (partition number)
w (write partition table to disk)

reboot server

mkfs.ext3 /dev/xvda3 (write file system to partition)
pvcreate /dev/xvda3 (Initialize the partition for use as a physical volume in lvm and add it to VolGroup)
vgextend VolGroup /dev/xvda3
lvextend -L +70G /dev/mapper/VolGroup-lv_root
resize2fs /dev/mapper/VolGroup-lv_root