The SunPlex system enables you to implement either failover or scalable services. In general, a failover service provides only high availability (redundancy), whereas a scalable service provides high availability along with increased performance. A single cluster can support both failover and scalable services.
Failover is the process by which the cluster automatically relocates a service from a failed primary node to a designated secondary node. With failover, Sun Cluster software provides high availability.
When a failover occurs, clients might see a brief interruption in service and might need to reconnect after the failover has finished. However, clients are not aware of the physical server that provides the service.
While failover is concerned with redundancy, scalability provides constant response time or throughput without regard to load. A scalable service leverages the multiple nodes in a cluster to concurrently run an application, thus providing increased performance. In a scalable configuration, each node in the cluster can provide data and process client requests.
Refer to Data Services for more specific information on failover and scalable services.