Purpose

JS7 implements resilience at the following levels:
- Architecture: Any components can be clustered for high availability, implementing an active-passive cluster architecture with automated fail-over.
- Components: Communication between components works asynchronously, practically this means that any component can be shut down or can be subject to an outage without breaking the availability of any other components. Components reconcile after restart and synchronize state information to catch-up with latest processing results.
- Programming: the programming model is based on asynchronous handling of events that are raised fir state transitions.

Clustering

The JOC Cockpit can be operated for an active-passive cluster with one active instance and any number of passive instances.
- Fail-over is handled automatically between cluster members.
- The JOC Cockpit cluster relies on a persistence layer provided by a supported DBMS.
The Controller implements an active-passive cluster with one active instance and one passive instance.
- The Controller implements clustering and journaling by its own and does not require additional components such as a DBMS.
- Cluster members couple and synchronize automatically.
The Agent offers both an active-passive and an active-active cluster.