David Heinemann

2021-10-09: Using an Eaton 3S 850 UPS with Unraid

For anyone in the market for an Unraid-compatible UPS...

Power outages are frequent where I live, especially as the storm season approaches. After reviving my home NAS, I decided it was time to protect my investment with a UPS.

I wanted to get an Eaton power supply, since I have had good experiences with them in the past. However, my NAS runs Unraid, and I had heard a lot of reports online that Eaton devices aren't compatible—at least, not without installing a third-party plugin. On the other hand, APC and CyberPower were well-supported and highly recommended.

After some research, I found that the Eaton 3S 850 UPS supports a HID-compliant USB interface. This is the same kind of interface as the APC devices I had seen recommended, so I decided to take a shot and order it. After connecting it to my NAS and enabling it in the Unraid UPS settings, it worked flawlessly. Quick testing showed that Unraid was able to detect a mains power outage (simulated by yanking the UPS power cord out), and perform a graceful shutdown.

So if you're looking for a UPS for Unraid, some Eaton devices certainly do work out-of-the-box.

My UPS settings in Unraid:

Start APC UPS daemon:Yes
UPS cable: USB
Custom UPS cable: (blank)
UPS type: USB
Device: (blank)