High Availability (HA) Clusters

Goal: Combine multiple systems and peripherals to appear as a single system that remains operational in the event of component failure.
NSPF - No Single Point of Failure
History: Implemented by proprietary vendors, typically requiring custom hardware. (i.e. VMS, TruCluster, SGI Failsafe, IBM Phoenix, NT Wolfpack)

Goal: Combine multiple systems and peripherals to appear as a single system that remains operational in the event of component failure.