My 2cents:
- For everyone, who knows hardware and OS in deep: use whatever you want, you’ll get it sorted anyways.
- For those, who don’t know hardware and OS: use openHABian with SD card
ad1:
you’re a pro. but don’t expect much support here in the forum as there’s a bazillion of possibilities, which can - and probably will - interfere in installation and integration into openHAB. openHAB is a web application - but the app is dependend to OS-level bindings or execs, or …
ad2:
if you don’t want to make a big head on how to run things - download openHABian and use it. It will take care of all the hassle of installation, integrations and operation of the web app as is. including solutions for monitoring and other helpers.
Plus: it comes ootb with backup/restore and migration tools.
which brings me to the “redundancy”-problem. If you’re a pro and use solution 1 - you should know how to deal with problems on hardware, OS and perhaps a bit of application level. You’re good. openHAB leaves you enough room for that. Install it on bare metal, in docker, kubernetes or proxmox - you’ll deal with it. Then you can deploy your new openHAB including restoring your data in no time if there’s a problem or even have HA-solutions in place for that automagically.
if you don’t want that - fine. openHABian helps you with that. you can clone your SD card regularly to a spare SD and plug it in the next Pi if there’s a hardware problem (I’ve got a bunch of Pis from the beginning - and still not a single one died on me since years!) or if the SD Card wears out. You can pro-actively change SD cards every bunch of years - or rely on your backup strategy (also openHABian functionality).
So, my 2cents. and most importantly my 3rd cent: Make up your mind (and possible free it!) on how you use a smarthome in principle. My definition e.g. is: my home mustn’t be dependend on my software. It works without it. openHAB (as any smarthome-software btw) is only there for convenience. If for some reason or another I can’t have my openHAB for days - I’m still be able to heat my house, turn on/off light or anything. Of course, it’s not as comfortable and I have to manually (eeeeh) press light buttons and stuff - but it works. no need for “booting from a SSD because I heard, SD cards only last a month” or so. 