Trouble setting up RAID 1

I have a server with 7 drives. two are 4TB, two are 2TB, and three are 1TB. I am attempting to install a new Ubuntu installation. I want to use one of the 1TB drives as my boot drive (I plan to replace it with a SSD to improve performance, just testing with it right now). I then want to create a 7TB RAID1 system with the remaining drives. I'd even settle with just a 4TB RAID1 system with the two 4TB drives.

When installing Ubuntu I did the manual partition configuration. I created a RAID1 set-up with 2 active drives and 0 spares. I selected my two 4TB drives as the active drives. I then created a LVM using one of the 1TB drives. I set the 1TB as bootable and the /root drive.

When booting into the system, I can't see the RAID drives. It seems like I only have 1TB.

bphillips@HTPC:~$ df -hFilesystem             Size  Used Avail Use% Mounted on
/dev/mapper/BOOT-BOOT  909G  1.3G  862G   1% /
udev                   3.9G  4.0K  3.9G   1% /dev
tmpfs                  1.6G  428K  1.6G   1% /run
none                   5.0M     0  5.0M   0% /run/lock
none                   3.9G     0  3.9G   0% /run/shm

My intended use for the server is to make a HTPC using Kodi.