LVM RAID1

pvcreate /dev/sdc /dev/sdd
vgcreate my_vg /dev/sdc /dev/sdd
lvcreate --type raid1 -m 1 -l 100%FREE -n my_lv my_vg

https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Logical_Volume_Manager_Administration/raid_volumes.html