I am building a video storage server at home, but I have ran into a problem in my plans. My original plan was to use TrueNAS Scale with ZFS and start with a mirrored vdev of two 18TB drives. I then wanted to expand it one 18TB drive at a time into a Z1 vdev of about 5 drives. However I found out from online research that it is not possible to just convert mirror vdev to a Z1 or even expand a Z1 vdev. Does a software raid solution exist where it is possible to start with just two drives, add other drives later and still keep the n+1 topology? This is the minimum I need, however the possibility to add an extra parrity drive would also be amazing. Let's say once I get to 5 drives (4+1) I could add an extra parrity drive to get 4+2. Is this somehow possible? If so what solution should I look into?