Depending on the model, you can change the speed of the fibre-channel ports on a SAN Volume Controller through the front panel on the SAN Volume Controller node or by a command sent to a SAN Volume Controller cluster using the Ethernet interface.
If you use SAN Volume Controller model 2145-8F4, 2145-8G4, 2145-8A4, or 2145-CF8 the speed of the fibre-channel ports is governed by the maximum speed of the fibre-channel switch to which the ports are connected, up to a maximum of 4 Gbps. The ports operate at the highest speed at which a reliable connection can be established. Different ports and nodes on the SAN Volume Controller can operate at different speeds.
All SAN Volume Controller 2145-4F2 and SAN Volume Controller 2145-8F2 fibre-channel ports and nodes on a SAN Volume Controller must operate at the same speed. The default for the port speed is 2 Gbps. If the fibre-channel fabric is using fibre-channel switches that are unable to operate at 2 Gbps, set the SAN Volume Controller fibre-channel port speed to 1 Gbps during the installation procedure. If you must replace a 2 Gbps fibre-channel switch with a 1 Gbps fibre-channel switch, you must manually switch the SAN Volume Controller fibre-channel port speed before you can use the SAN Volume Controller at 1 Gbps.
If a new SAN Volume Controller 2145-8F2 node is added to an existing SAN Volume Controller configuration, you must change the speed setting if the switch is only capable of running at 1 Gbps. If the SAN Volume Controller internal disk drive fails, the fibre-channel speed setting is lost, but the Node Rescue Procedure that you use to restore the SAN Volume Controller software automatically selects the correct speed. If a 1 Gbps fibre-channel switch is being replaced by a 2 Gbps fibre-channel switch, the existing SAN Volume Controller clusters operate at 1 Gbps. You can switch to 2 Gbps any time using the command-line interface.