Tdd Apps

# Lessons from building a Raspberry Pi 4 NAS

May 5, 2020 2 minute read

I built a home NAS with a Raspberry Pi 4. It took longer than expected. The end result is not as great as I originally envisioned. These are some bits of hard-earned knowledge to save you time and pain.


USB 3 support is not great. I tested at least four different drives and as many drive enclosures. Powered USB hubs. Even powered hard drive enclosures. Drives just disconnect regularly.

This forum post helped mitigate some USB problems. However, I found no reliable way to copy hundreds of gigabytes over USB. I had to copy the bulk of the data on my laptop.

File System

Since I had to plug the NAS disk to my laptop, file system selection was harder.

I chose Ex-FAT. It comes native on Mac OS and can be installed on Linux. However, mount.exfat CPU usage becomes high at times.

Operating System

Use Raspbian to minimize friction. Most documentation and examples are based on it.

I tried Ubuntu first. But some things work differently (e.g. /boot/cmdline.txt is in /boot/firmware/nobtcmd.txt).

Power Supply

Get the Official Power Supply. The Raspberry Pi 4 comes with a USB-C charging port. But this port is not entirely compliant with the USB-C standard. Incompatible cables and power supplies cause throttling.

Monitor your computer physical parameters. Voltage, temperature, etc. If the board gets too hot it will get throttled. The vcgencmd is very useful to troubleshoot these issues.


Automate your setup. I created a few ansible playbooks for provisioning. These playbooks are the NAS core.

I tried many different approaches because I had the automation to reduce variance and manual errors. Ultimately, this NAS will be moved to a different computer and the ansible playbooks will help me do it.


Building a NAS out of a Raspberry Pi is a good learning experience for those who want to learn more about Linux administration.

Is it worth the time and effort compared to an off-the-shelf solution? It depends.

This NAS is not suitable for high volume loads. But it is silent, small, and has a close to zero power consumption. It is built on a general purpose computer and operating system. It has no proprietary restrictions. It gets regular security updates. It gives you control to tailor it to your needs.

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