Mix together one Raspberry Pi and a sprinkle of cheap external hard drives and you have the recipe for an ultra-low-power and always-on network storage device. Read on as we show you how to set up your own Pi-based NAS.
https://www.howtogeek.com/139433/how-to-turn-a-raspberry-pi-into-a-low-power-network-storage-device/
https://www.howtogeek.com/139433/how-to-turn-a-raspberry-pi-into-a-low-power-network-storage-device/