Working with Portal Server Building Modules
Building Modules and High Availability Scenarios
Portal Server provides three scenarios for high availability:
•Best Effort
The system is available as long as the hardware does not fail and as long as the Portal Server processes can be restarted by the watchdog process.
•No Single Point of Failure
The use of hardware and software replication creates a deployment with no single point of failure (NSPOF). The system is always available, as long as no more than one failure occurs consecutively anywhere in the chain of components. However, in the case of failures, user sessions are lost.
•Transparent Failover
The system is always available but in addition to NSPOF, failover to a backup instance occurs transparently to end users. In most cases, users do not notice that they have been redirected to a different node or instance. Sessions are preserved across nodes so that users do not have to reauthenticate. Portal Server services are stateless or use checkpointing mechanisms to rebuild the current execution context up to a certain point.
Possible supported architectures include the following:
•Using Sun™ Cluster software on components that support Sun Cluster agents
•
This section explains implementing these architectures and leverages the building module concept, from a
