Balancing Traffic Through Logical Unit Range Partitioning

An approach is provided in which a storage system includes a first storage controller, a second storage controller, and multiple logical units. The storage system detects that a controller traffic load ratio between the first storage controller and the second storage controller has reached a threshold. As such, the storage system selects one of the logical units and partitions the selected logical unit into multiple logical units. The storage system, in turn, changes a preferred controller ownership of one of the logical unit partitions from the first storage controller to the second storage controller.