From high availability and disaster recovery to business continuity solutions.

We first provide an overview of the state-of-the-art architectures for continuous availability, briefly covering such traditional concepts as high-availability (HA) clustering on distributed platforms and on the mainframe. We explain how HA can be achieved in environments based on Sun Microsystems J2EE™, which differ from classical clustering approaches, and we discuss how disaster recovery (DR) has become an extension of HA. The paper then presents aspects of service management, including the use and orchestration of process-based (ITIL®) systems management tasks within DR scenarios, where the key challenge is to ensure the right level of redundancy in the integration and service-oriented management of heterogeneous information technology landscapes. [ABSTRACT FROM AUTHOR]