Mount USB hard drive on boot

I’m trying to mount a USB hard drive on my nerves device at boot, I am using a custom system, so I have some flexibility.

But I’ve tried adding a -m directive to my erlinit.config as well as just mounting it in my application and it isn’t working.

If I am mounting to /root/uns/ does the filesystem on the USB drive have to match the file system on the card?

I added the ExFat and ExFat utilities to my system, and I tried using exfat as a disk format, and others. What disk format should I be using?

Any other ideas are welcome. My goal is to get postgres and influx installed and saving their data to the USB drive as well as a Phoenix app that can store uploads there.

Thanks in advance!