Step 1: If md raid setup:
#sudo apt-get install mdadm
To tell it to look for arrays and create devices for them:
#sudo mdadm --assemble --scan
You should get a response like this:
# mdadm: /dev/md0 has been started with 2 drives.
From here, everything is like with ordinary block devices. To mount the device:
#sudo mount /dev/md0 mnt
and continue with step 2..