sudo apt-get install btrfs-tools
# mkfs.btrfs /dev/sdb
sudo mkfs.btrfs -L lxc /dev/sdb1

# list volumes
btrfs filesystem show

# list subvolumes
mount /dev/sdb1 /mnt/
btrfs subvolume list /mnt/

# create subvolume
sudo btrfs subvolume create /mnt/@sub1

# get default subvolume
btrfs subvolume get-default /mnt/

# set default subvolume
btrfs subvolume set-default 299 /mnt/

# mount subvolume
mount -o subvol=new_subvol /dev/sdb1 /tmp/2

btrfs filesystem resize 64g /mnt

# enable comprsssion (mountparameter)
compress

# /etc/fstab
/dev/sda        /       btrfs   rw,autodefrag,compress=lzo,noatime,thread_pool=16       00

# directroy to subvolume?
# mv /var/lib/lxc/installserver /var/lib/lxc/installserver_tmp
# btrfs subvol create /var/lib/lxc/installserver
# time cp -a --reflink /var/lib/lxc/installserver_tmp/rootfs /var/lib/lxc/installserver

# create snapshot
sudo btrfs subvolume snapshot / /@snap1

# list snapshots
btrfs subvolume list /

# delete snapshot
btrfs subvolume delete /@snap1

Links
http://wiki.ubuntuusers.de/Installieren_auf_Btrfs-Dateisystem
http://wiki.ubuntuusers.de/Befehle_Btrfs-Dateisystem