With the emergence of data-intensive applications, recent years have seen a fast-growing volume of I/O traffic propagated through the local I/O interconnect bus. This raises up a question for storage systems: how to efficiently manage the increasing I/O traffic and improve storage performance. In this paper, we propose a new hierarchical data cache architecture for iSCSI (Internet Small Computer System Interface) storage systems. The proposed architecture consists of a hierarchical cache structure, which includes a small on-chip cache, a larger off-chip cache, and a storage device. The on-chip cache is used to store frequently accessed data, while the off-chip cache is used to store less frequently accessed data. The storage device is used to store data that is not frequently accessed. The proposed architecture is designed to improve storage performance by reducing the number of I/O requests and improving data locality. We evaluate the proposed architecture using a simulation-based approach and show that it can improve storage performance by up to 30% compared to traditional iSCSI storage systems.