Home > Data Protection > PowerProtect DD Series Appliances > White Papers > Dell EMC PowerProtect DD 6400 > Capacity and licensing
A DD6400 base model starts with 2U and a minimum capacity of 8 TB. You can increase capacity in increments of 4 TB with license. For active tier, the maximum capacity is 32 TB; for cloud tier, the maximum capacity is 64 TB.
Adding a first ES40 expansion shelf provides additional capacity of from 40 TB to 104 TB. The maximum cloud tier license supports 208 TB. When expanding capacity, a second SSD cache disk must be configured in order to avoid any errors.
Adding a second ES40 expansion shelf provides additional capacity of from 112 TB to 172 TB. The maximum cloud tier license supports 344 TB.