After 9/11 and the accidental failure of the power grid in North America in 2003, storage area network (SAN) extension has emerged as critical to ensuring business continuity. However, SAN extension encounters challenges in the access network, including scalability problems, cost challenges, bandwidth bottlenecks and low throughput. In this article, we propose a new solution to address these problems: SAN extension over passive optical networks (S-PONs). To tackle the scalability problems and cost challenges, we designed the S-PON architecture based on the existing point-to-multiple-point (P2MP) PON infrastructure. To address the bandwidth bottlenecks in SAN extension, we propose three solutions for carrying storage signals with gigabit-level transmission. We also introduce a new device, XtenOLT, for implementing buffer pools by a new buffer-management scheme to improve SAN extension throughput and utility. Our experimental results show that, in the physical layer, the proposed S-PON transmission technologies successfully deliver SAN traffic to the long-haul at the rate of 2.5 Gb/s; in the network layer, S-PON with XtenOLT dramatically enhances deliverable throughput and utility over long-distance transmission.