Replicating data across application servers in a cluster

 

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Overview

Use this task to configure a data replication domain to transfer data, objects, or events for session manager, dynamic cache, or stateful session beans. Data replication domains use the data replication service (DRS), which is an internal WAS component that performs replication services, including replicating data, objects, and events among application servers.

 

Before you begin

If you configured a data replication domain with a previous version of WAS, you might be using a multi-broker replication domain. Any replication domains that you create with the current version of WAS are data replication domains. Migrate any multi-broker replication domains to data replication domains.

To learn the differences between the two types of replication domains, see...

• Comparison of multi-broker versus data replication domains
• Migrating V6.0 servers from multi-broker replication domains to data replication domains

 

Overview

Use this task to configure replication, a service that transfers data, objects, or events among the application servers in a cluster. Use replication to prevent loss of session data with session manager, to further improve the performance of the dynamic cache service, and to provide failover in stateful session beans. For more information about replication, see Replication.

 

Procedure

1. Create a replication domain. Use one of the following methods to create a replication domain:

   • Create a replication domain manually.

     To create a replication domain manually without creating a new cluster, click Environment > Replication domains > New in the administrative console.

     On this page one can specify the properties for the replication domain, including timeout, encryption, and number of replicas. See Data replication domain settings for more information about the properties that you can configure for your replication domain.

   • Create a replication domain when creating a cluster.

     To create a replication domain when you create a cluster, click Servers > Clusters > New in the administrative console. Enable Create replication domain for this cluster. The replication domain that is created has the same name as the cluster and has the default settings for a replication domain. The default settings for a replication domain are to create a single replica of each piece of data and to have encryption disabled. To modify the replication domain properties, click Environment > Replication domains > replication_domain_name in the administrative console. See Creating clusters for more information about creating a cluster.

   For more information about the replication domain settings that one can configure in the administrative console, see Data replication domain settings

2. Configure the consumers, or the components that use the replication domains. Dynamic cache, session manager, and stateful session beans are the three types of replication domain consumers. Each type of consumer must be configured with a different replication domain. For example, session manager uses one domain and dynamic cache uses a different replication domain. However, use one replication domain if you are configuring HTTP session memory-to-memory replication and stateful session bean replication. Using one replication domain in this case ensures that the backup state information of HTTP sessions and stateful session beans are on the same application servers.

   • To configure dynamic cache replication, see Configuring cache replication.

   • To configure memory-to-memory replication for session manager, see Configuring memory-to-memory replication for the peer-to-peer mode (default memory-to-memory replication).

   • To configure replication of stateful session beans, see Enabling or disabling stateful session bean failover with the EJB container panel.

 

Result

Data is replicating among the application servers in a configured replication domain.

 

What to do next

If you use the Data Encryption Standard (DES) or DES3 encryption type for a replication domain, an encryption key is used for the encryption of messages. Click Regenerate encryption key on the Data replication domain settings page at regular intervals to regenerate the key and protect your configuration. After the key has been changed or regenerated, restart all of the application servers that are configured as part of the replication domain. Consider performing this step every month to secure your configuration.

 

See also

Replication
Replication domain collection
Migrating V6.0 servers from multi-broker replication domains to data replication domains
Replicating data with a multi-broker replication domain