Which technology should a customer choose to directly connect an external storage array?

The correct choice is SAS (Serial Attached SCSI) because it is a widely used technology for directly connecting external storage arrays, providing high-speed and reliable data transfer between servers and storage devices. SAS supports both point-to-point and multipoint configurations, eliminating the bottlenecks associated with older technologies. It enables robust performance and scalability, making it suitable for enterprise-level applications where direct connectivity to external storage is critical.

In addition, SAS supports connections to multiple devices and allows for daisy-chaining, which enhances flexibility in storage configurations. This makes it an excellent choice for environments where high bandwidth and low latency are essential for optimal storage performance.

While other technologies listed, such as FICON and ESCON, are primarily used in mainframe environments, and FCoE is designed for integrating Fibre Channel into Ethernet networks, they are not specifically tailored for the direct attachment of external storage arrays in the same manner that SAS is.