What is required to add additional controllers to an existing HUAWEI OceanStor system?

In order to add additional controllers to an existing HUAWEI OceanStor system, a FC (Fibre Channel) or iSCSI (Internet Small Computer System Interface) Host Bus Adapter (HBA) is required. The HBA connects the controller to the storage devices, and it is required to add additional controllers to the system. The HBA provides the interface between the controller and the storage devices, and it allows the controller to communicate with the storage devices over the FC or iSCSI protocol. Other options such as SAS cabling, 56 Gb Infiniband module, and Smart I/O card are also important components in storage systems, but they are not directly related to adding additional controllers to an existing HUAWEI OceanStor system.