Hello tradsd, When you activate the Premium features on your MD3220 in MDSM (Modular Disk Storage Manger) they are active for the whole unit including both controllers & any attached enclosures.  If in the event that you have a failure of a connection on the controller or a controller needs to be replaced the license will still stay active & will attach to the replacement controller as well. Please let us know if you have any other questions.
I just hooked up a new dual controller MD3220 and had a question about managing the premium features.  I went to md-storage.com and got the license key after entering the feature activation code, serial and identifier.  I've successfully imported the key and now have access to the high performance tier and ssd cache.  I was sent 2 "DO NOT DISCARD, PREMIUM FEATURE ACTIVATION CODE" envelopes.  My question is what I've done thus far, does that cover both controllers?  Or do I need to go through that process again on the other controller.  When I connect to the controller as you all know I'm seeing or configuring the setup for both controllers.  I don't see a way to add another license key but don't want to run into the situation where a failover occurs for whatever reason to the second controller and the features aren't enabled.  Does the key and enabling it cover both controllers?  Just want to make sure I'm good. 
PowerVault MD3200 Premium Feature Activation - 2 codes??