In order to enable btrfs storage driver instead of AUFS in Fedora 20 we have to:
1) Create a partition or logical volume with btrfs and mount it in /var/lib/docker, for example in my case:
# yum install -y btrfs-progs # lvcreate -l 100%FREE -n docker fedora # mkfs.btrfs /dev/fedora/docker # echo '/dev/mapper/fedora-docker /var/lib/docker btrfs defaults 1 2' >> /etc/fstab
2) Install Docker
# yum -y install docker-io # mount -a # vi /usr/lib/systemd/system/docker.service ... ExecStart=/usr/bin/docker -d -s btrfs ... # systemctl start docker # systemctl enable docker
3) Check that Docker is using btrfs as storage driver
# docker info Containers: 0 Images: 4 Storage Driver: btrfs Execution Driver: native-0.1 Kernel Version: 3.13.9-200.fc20.x86_64