I have a Pro license. I would like to have 2 cache drives but I only have the option to select 1. I read on another post that you need to decrease the array slots, but I am unable to decrease the array slots - I only have the option to select 24. I assume this is because I have a drive assigned to slot 23. My total number of assigned drives however is only 10. Is my assumption correct? If so I believe I have to move the drive to a lower slot and to do that I have to do a "New Config" but I understand this will invalidate parity. I would prefer not to invalidate parity so I am asking do I have any other option(s)?

A new config won’t invalidate parity, just do it and reassign all your disks, make sure you assign parity to the parity slot, before starting the array check the box “parity is already valid”.

Thanks Johnnie, that worked.