You are diagnosing a performance problem with a Fibre Channel attached server that is configured to run multipathing with dynamic I/O load balancing. You are not seeing the expected performance. You h

Fibre Channel operates in full-duplex mode by default; half-duplex is highly uncommon and would drastically reduce performance, but typically wouldn't be a configuration issue with modern FC.

A cache-centric architecture usually implies that the cache is the primary point of data access, often distributed or highly available, which generally improves performance rather than hindering it.

Full duplex is the standard and desired operating mode for Fibre Channel, enabling simultaneous send and receive, thus improving performance rather than causing issues.

In a controller-centric storage architecture, all I/O for a specific LUN or set of LUNs is typically served by a single, active controller, even if multiple paths exist to the storage system. This means that while the server has multiple paths to the storage, the I/O processing on the storage array itself is bottlenecked by the designated controller, limiting the total throughput regardless of multipathing software.