Configuring Session State Replication Across Clusters

6-14 Using Clusters for Oracle WebLogic Server ■ When setting up your domains, you must enable trust between both domains. For more information on enabling trust between domains, see Enabling Trust Between WebLogic Server Domains in Securing Oracle WebLogic Server 4. If you are using cross-cluster replication in a WAN environment, you must create a data source that is used to maintain session state. For more information, see Section 6.2.4.6.3, Database Configuration for WAN Session State Replication. 5. After you have created and configured your domains, servers, and clusters you should verify the configuration elements specific to cross-cluster replication have been configured correctly. These parameters must be configured identically for both domains. Table 6–2 lists the subelements of the cluster element in config.xml that are used to configure cross-cluster replication:

6.2.4.3 Configuring Session State Replication Across Clusters

You can use a third-party replication product to replicate state across clusters, or you can allow WebLogic Server to replicate session state across clusters. The following configuration considerations should be kept in mind depending on which method you use: ■ If you are using a third-party product, ensure that you have specified a value for jdbc-pool, and that backup-cluster-address is blank. ■ If you are using WebLogic Server to handle session state replication, you must configure both the jdbc-pool and the backup-cluster-address. Table 6–2 Cluster Elements in config.xml Element Description cluster-type This setting must match the replication type you are using and must be consistent across both clusters. The valid values are man or wan remote-cluster-address This is the address used to communicate replication information to the other cluster. This should be configured so that communications between clusters do not go through a load balancer. replication-channel This is the network channel used to communicate replication information to the other cluster. Note: The named channel must exist on all members of the cluster and must be configured to use the same protocol. The selected channel may be configured to use a secure protocol. data-source-for-session-persistence This is the data source that is used to store session information when using JDBC-based session persistence. This method of session state replication is used to perform cross-cluster replication within a WAN. For more information, see Section 6.2.4.6.3, Database Configuration for WAN Session State Replication. session-flush-interval This is the interval, in seconds, the cluster waits to flush HTTP sessions to the backup cluster. session-flush-threshold If the number of HTTP sessions reaches the value of session-flush-threshold, the sessions are flushed to the backup cluster. This allows servers to flush sessions faster under heavy loads. inter-cluster-comm-link-health-check-interval This is the amount of time, in milliseconds, between consecutive checks to determine if the link between two clusters is restored. Failover and Replication in a Cluster 6-15 If backup-cluster-address is NULL, WebLogic Server assumes that you are using a third-party product to handle replication. In this case, session data is not persisted to the remote database, but is persisted locally.

6.2.4.4 Configuring a Replication Channel