Recently had to go through an exercise of downsizing the cache array on an encrypted array (and encrypted cache array).
Only way to do so was via:
1. Tools -> New Config -> Preserve current assignments [Array slots].
2. wipefs -a /dev/sd[y-z] # (clear filesystem from cache drives)
3. assign cache drives
4. Mark 'parity is already valid'
5. Start array
6. encounter unmountable drives
The array was hosed at this point, can someone confirm this for me? have rebooted the server and re-created the array since data on it wasn't important, still pretty disappointing. The error was the partitions were not recognized.