pi@raspberrypi:~$ sudo apt-get install lvm2
pi@raspberrypi:~$ sudo pvcreate /dev/mmcblk0p4
pi@raspberrypi:~$ sudo lvcreate jdbLV /dev/mmcblk0p4
pi@raspberrypi:~$ sudo vgcreate jdbVG /dev/mmcblk0p4
pi@raspberrypi:~$ sudo lvcreate --name gloriousLV --size 1G jdbVG
pi@raspberrypi:~$ ls -l /dev/mapper
pi@raspberrypi:~$ ls -l /dev/jdbVG/gloriousLV
pi@raspberrypi:~$ sudo mkfs -t ext4 /dev/jdbVG/gloriousLV
pi@raspberrypi:~$ sudo mkdir /tmp/glorious
pi@raspberrypi:~$ sudo mount /dev/jdbVG/gloriousLV /tmp/glorious
pi@raspberrypi:~$ df /tmp/glorious