A retail company is planning to create a web shop on their website to offer their products and services. They expect a large increase in sales and increased traffic to their website, which will result

Adding more disks to an EVA storage array directly increases the number of available spindles, which distributes I/O load and improves overall throughput and response latency. The question explicitly identifies increased disk I/O as the key challenge, and more spindles allow the array to serve more concurrent I/O requests. This directly addresses the customer's requirement for fast website response times and high customer satisfaction.

Adding server memory improves compute performance and OS-level caching but does not resolve an underlying disk I/O bottleneck at the storage array level.

Adding blade servers increases compute capacity but does not address the disk I/O constraint that is the identified performance bottleneck in the EVA storage array.

Adding HBAs increases the bandwidth path between servers and the SAN but cannot resolve I/O limitations caused by insufficient disk spindles inside the storage array itself.