Quick and dirty notes from the original AWS Documentation.
[[ ! -z $(sudo file -s /dev/xvdf | grep -e 'data$') ]] && sudo mkfs -t ext4 /dev/xvdf
[[ ! -z $(sudo file -s /dev/xvdg | grep -e 'data$') ]] && sudo mkfs -t ext4 /dev/xvdg
sudo mkdir -p /mnt/{data,tmplog}