How many active I/O paths should there be between each director and every BE storage array?

In a VPLEX environment, having two active I/O paths between each director and every back-end (BE) storage array is essential for achieving high availability and load balancing. This configuration allows for path redundancy, ensuring that if one path fails, the other can maintain the connection, thus preventing disruptions in data access and maintaining system performance.

The use of two active paths also facilitates better load distribution during simultaneous read and write operations. This setup is critical for maximizing throughput and minimizing latency, as multiple paths enable the I/O requests to be spread across different connections, ultimately enhancing the overall efficiency of the storage architecture.

While having fewer paths might seem sufficient, it would introduce single points of failure, compromising the system's resilience and performance. More than two paths could also complicate the configuration and management of the I/O infrastructure without providing proportional benefits in typical environments. Therefore, two active I/O paths strike an optimal balance between reliability and complexity in the VPLEX design.