We have 12 TB and 4 TB licence , from the beginning as we planned to use failover and so on, but we never use 4 TB licence as we have no second SAN. 12 TB licence its installed on old SAN, but it this SAN have less than 4 TB after RAID 5, because the idea was that we will extend the drives in future and it was long time ago. Now we have new server and hard drives become larger and cheaper, so we can get 12 TB capacity. Finally we can use our 12 TB licence and 4 TB licence.