Fibre Channel Buffer Credit Adjustment for Remote Copy Throughput

The patent applies preliminary action by pre-calculating and setting the BB credit value based on the known distance between sender and receiver ports before data transfer begins. The storage control unit determines the appropriate BB credit value in advance using the distance information, rather than adjusting it dynamically during transfer. This eliminates the need for complex real-time buffer management while ensuring sufficient buffers are allocated to handle the line delay, thus maintaining throughput without increasing operational complexity.

The patent applies parameter changes by adjusting the BB credit value parameter based on the distance parameter. The storage control unit changes the BB credit parameter to match the specific distance between ports, ensuring that the buffer allocation is optimized for each particular connection scenario. This targeted parameter adjustment maintains data transfer continuity by providing sufficient buffers for the specific line delay, while avoiding the unnecessary allocation of excess buffer memory that would occur with a fixed high BB credit value for all distances.