The demands of business processing necessitate maximum uptime from computing resources. Accepting this and dealing with it presents a whole new set of challenges. A key component in HP-UX high-availability solutions is a thorough understanding of Serviceguard. We look at Serviceguard solutions including Extended Serviceguard clusters, Metrocluster, and Continentalclusters. Accompanying many of these solutions will be highly available access to data, commonly held on a highly available disk array. We look at some of the infrastructure issues surrounding remote access to fibre channel disk arrays: technologies such as “dark fibre” and DWDM, which ultimately leads us to a discussion on SANs.