Page History

...

The documentation frequently indicates a Primary Controller Instance and a Secondary Controller Instance. The names suggest that one Controller Instance is primarily used and one is for backup purposes.

• The wording in of cluster terms suggests to indicate the Active Controller Instance and the Standby Controller Instance independently from the fact if the Primary or Secondary Controller Instance is active.
• A Controller implements an active-passive cluster, however, the term passive is misleading as the Standby Controller Instance is not passive at all but records any order state transitions occurring in the Active Controller Instance. Both Controller instances hold a journal of order state transitions that is actively synchronized. Fail-over and switch-over will occur only if both Controller instances' journals are in sync.
• The Cluster presents itself as a single unit to the outside world, i.e. to JOC Cockpit and to Agents.
  • Any operations performed in JOC Cockpit are automatically applied to the Active Controller Instance.
  • At any point in time only one Controller instance is active and the other instance is in standby mode.

...