pi@raspberrypi:~$ sudo apt-get install lvm2
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following NEW packages will be installed:
  lvm2
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 578 kB of archives.
................................................................
Setting up lvm2 (2.02.95-8+rpi1) ...
Setting up LVM Volume Groups...  
  No volume groups found
done.
update-initramfs: deferring update (trigger activated)
Processing triggers for initramfs-tools ...
pi@raspberrypi:~$ sudo pvcreate /dev/mmcblk0p3
  Writing physical volume data to disk "/dev/mmcblk0p3"
  Physical volume "/dev/mmcblk0p3" successfully created
pi@raspberrypi:~$ sudo vgcreate sysadmVG /dev/mmcblk0p3
  Volume group "sysadmVG" successfully created
pi@raspberrypi:~$ sudo lvcreate --size=256M --name=aLV sysadmVG
  Logical volume "aLV" created
pi@raspberrypi:~$ ls -l /dev/sysadmVG/aLV 
lrwxrwxrwx 1 root root 7 Mar 31 10:27 /dev/sysadmVG/aLV -> ../dm-0
pi@raspberrypi:~$ ls -lL /dev/sysadmVG/aLV 
brw-rw---T 1 root disk 254, 0 Mar 31 10:27 /dev/sysadmVG/aLV
pi@raspberrypi:~$ sudo mkfs -t ext4 /dev/sysadmVG/aLV
mke2fs 1.42.5 (29-Jul-2012)
Discarding device blocks: done                            
Filesystem label=
OS type: Linux
Block size=1024 (log=0)
Fragment size=1024 (log=0)
Stride=0 blocks, Stripe width=0 blocks
65536 inodes, 262144 blocks
13107 blocks (5.00%) reserved for the super user
First data block=1
Maximum filesystem blocks=67371008
32 block groups
8192 blocks per group, 8192 fragments per group
2048 inodes per group
Superblock backups stored on blocks: 
	8193, 24577, 40961, 57345, 73729, 204801, 221185

Allocating group tables: done                            
Writing inode tables: done                            
Creating journal (8192 blocks): done
Writing superblocks and filesystem accounting information: done

pi@raspberrypi:~$ mkdir /tmp/a
pi@raspberrypi:~$ sudo mount /dev/sysadmVG/aLV /tmp/a
pi@raspberrypi:~$ df
Filesystem               1K-blocks    Used Available Use% Mounted on
rootfs                     8191672 2643492   5165160  34% /
/dev/root                  8191672 2643492   5165160  34% /
devtmpfs                    470368       0    470368   0% /dev
tmpfs                        94936     220     94716   1% /run
tmpfs                         5120       0      5120   0% /run/lock
tmpfs                       189860       0    189860   0% /run/shm
/dev/mmcblk0p1               57288   14720     42568  26% /boot
/dev/mapper/sysadmVG-aLV    245679    2062    226414   1% /tmp/a
pi@raspberrypi:~$ ls /tmp/a
lost+found
pi@raspberrypi:~$ exit