The documents referenced here describe a concept and sofware products that support High Availability (HA). The software product discussed here is from IBM and is called High Availability Clustered Multi-Processing (HACMP).
High Availability refers to the attempt to minimize downtime to business functions by eliminating single points of failure (SPOF's). This requires duplicating systems, networks, storage, and sofware to eliminate these SPOF's.
vLPAR Automated Deployment Appliance for Business Continuity, Disaster Recovery, High Availability, and Virtualization