To answer your second question, I think the answer is generally yes, because loss of any vdev in a pool means the entire pool is lost. For example, if you init

To answer your second question, I think the answer is generally yes, because loss of any vdev in a pool means the entire pool is lost. For example, if you initially created the pool with a single raidz2 vdev, probably the only way it makes sense to add a second raidz1 vdev is if you later changed your mind about how important your data is.