Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?

sudo dockerd \
      --storage-opt dm.datadev=/dev/sda1 \
      --storage-opt dm.metadatadev=/dev/sdf

INFO[0000] libcontainerd: previous instance of containerd still alive (1271)
INFO[0000] [graphdriver] using prior storage driver: aufs
Error starting daemon: error while opening volume store metadata database: timeout

$ systemctl daemon-reload
$ sudo service docker restart
$ sudo service docker status (should see active (running))
$ sudo docker run hello-world