Load-balanced configuration model
The load-balanced topology consists of a highly available application server cluster, an HTTP server cluster, a database cluster, and a directory server cluster.
In a load-balanced topology, services are highly available because all components are either in active-active mode or in hot-standby mode. A high volume of users can access the system simultaneously, with minimal impact on operations. This topology is commonly used because it also addresses performance and scalability of the infrastructure, and it can be used with the advanced configurations.
- Failover of WebSphere® Application Server is managed by WebSphere Application Server Network Deployment. Configuration data is replicated to every node agent in the cell, so the impact of a deployment manager failure on the application client processing is limited. When the deployment manager server becomes available again, all node agents in the cell reactivate and service returns to normal.
- The HTTP server is supported by a standby server, which becomes active when the primary HTTP server fails.
- The database server can be automated to run on a primary database server and a standby database server. Automated failover and data integrity is handled by DB2® HADR. If the primary database server fails, the services are automatically restored on the standby database server.
- Security Directory Server can be configured in a load-balanced environment by introducing a highly available proxy server. In this scenario, both Security Directory Server instances are running and synchronized through peer-to-peer replication. If one of the directory servers fails, the proxy automatically directs the requests to the next active instance. A primary server and a standby proxy server are configured in a warm standby configuration with highly available shared storage. The shared disk provides a common installation directory and is mounted only on the active server. If the primary proxy server fails, the standby server can be automatically started up by the cluster manager. If one of the directory servers fails, the proxy automatically directs the requests to the next active instance.
The following diagram shows a load-balanced topology, where a product such as Maximo® Asset Management is deployed in a scaled WebSphere Application Server Network Deployment environment.
Standby servers provide failover support for each component and a highly available shared file system is used to store attachments and other files. As individual components, the HTTP server, the database server, and the directory server are all highly available. WebSphere Application Server Network Deployment manages the application server nodes in the system.
