You must migrate and store your database in correctly sized and appropriately configured LUNs. Use the minimum possible number of LUNs for faster backup operations and faster restore operations. You must group your databases if you do not need to restore them individually.
Determine how many LUNs you need for your SnapManager configuration and what data those LUNs hold. Then create your data configuration plan by calculating the required sizes for each LUN and the volume that contains it.