Which of the following is the BEST way to increase performance of a storage array?

Using larger capacity drives increases the storage space available but does not inherently improve the performance metrics like IOPS or throughput, as it's still one physical drive.

Increasing the number of spindles (individual physical hard drives) in a storage array is a fundamental way to enhance performance, particularly in terms of IOPS (Input/Output Operations Per Second). More spindles allow the array controller to distribute I/O requests across more devices concurrently, leading to higher aggregate read and write speeds and better responsiveness.

SATA drives are generally designed for cost-effectiveness and higher capacity, often providing lower performance (fewer IOPS, lower throughput) compared to SAS or NVMe drives, thus using them would likely decrease performance.

Decreasing the number of attached hosts reduces the demand on the storage array but does not increase its intrinsic performance capabilities or hardware throughput for handling I/O.