

HA is definitely the largest adopted. OpenHab is probably more geared for developers, but has a more concise and powerful automation system.
As for hardware to run it on: get a cheap n100 Minipc and be done with it. Uses 6-12W, and it’s going to miles.kore efficient for this use than a regular PC.







If you’re going for reliability, and you just want things to be simple, you probably just want to spend the money on two cheap NAS boxes, honestly. There are some caveats that come with RPi’s, and you’re unfamiliar it’s: 1) going to cost about the same, 2) be simpler to manage and upgrade, and 3) be easier to repair disk columes when the time comes.
Even if you’re just looking to make these redundant to each other, just make it simple and easy.