The problem is, I have six SATA holes on my mobo, and this array is using the last four. The first is used by my boot+home drive, sda. If I add a sixth drive in the second slot, that becomes sdb, and everything else bumps down. The RAIDZ array goes mental, and says that the first drive is wrong, and the other three are corrupted. The solution, as I see it, is to change the drives in the array to be defined by their UUIDs, as opposed to their node names. That way, it doesn't matter what happens. The only way I can figure out to do this is to remove a drive, and readd it under a different name. Unfortunately, it seems impossible to remove a device from a RAIDZ.
So my question is, can I do what I want to do? Backing everything up from the array is possible, but I would rather not, since it's 3.7 TB, and I would be borrowing HDDs for this. Any help would be great.