Thanks a lot for this very in depth response! I had to take some time to sit down and properly understand everything so sorry for the late response.

I will take your advice seriously and buy at least three drives of the same size (to get this right, the model or brand doesn’t necessarily need to be the same right?). Because I don’t know if I can afford four of the size I would like to get. One question I still have is, how do you achieve the hot standby? Is this a software feature common NAS OS provide?