SIMULATION - Create a 512M partition, make it as ext4 file system, mounted automatically under /mnt/data and which take effect automatically at boot-start. 

See explanation below.

# fdisk /dev/vda n +512M w # partprobe /dev/vda # mkfs -t ext4 /dev/vda5 # mkdir -p /data # vim /etc/fstab /dev/vda5 /data ext4 defaults 0 0 # mount -a