I've been using TrueNAS for six years already. I've built a custom server
- Intel dual core Atom CPU
- Passive cooling for the CPU, two fans for the HDDs
- A small Supermicro motherboard with IPMI and six SATA connectors
- 16 gigabytes of ECC RAM
- Six 14 terabyte hard disks
- Fractal Design Node case
- ZFS with RAIDz2
But this setup is getting old, I've had a few errors already from the CPU. My plan next year is to build a rack server with a modern AMD Ryzen CPU, 64 GB of RAM, Proxmox with TrueNAS scale in a virtual machine and re-use the disks I have in the current setup.
Proxmox is much nicer for virtual machines and LXC, and if you need Docker, you can run them in the TrueNAS Scale VM.
Hardware wise I bought a TerraMaster F4-423 used last year for about 300€. It's a great device.
Software wise, I use Fedora Server, although if I had to reinstall now I would use AlmaLinux because I don't need the new stuff coming with Fedora Server on my NAS.
