at the moment I’m doing only a “Backup openHAB Config” in openHABian Configuration Tool.
Is this sufficient or would you rather also recommend to “Setup SD mirroring”?
For SD mirroring I would use a 128GB backup card, the main card is 32GB.
In case main card fails I would put the 128GB backup card into the internal reader. Can I then do a Raw copy back to a 32GB or even 16GB microSD card?
I’d say if you are doing regular backup manually there is no real need to do additional SD card mirroring. That being said the SD card mirroring is extremely easy and cheap to implement and gives you the ability to recover your most current config regardless of when you pulled your last manual backup.
I do both myself.
That isn’t a backup tool, you just export the config.
Read up on a proper concept here and setup Amanda.
SD mirroring isn’t a ‘backup’ either.
It’s an ultra-fast system recovery mechanism that you can even conduct from remote.