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 WebSphere Application Server component that performs replication
services, including replicating data, objects, and events among application
servers.
About this task
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
- 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 you 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 you create 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 you can configure in the administrative console, see Data replication domain settings
- 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.
- Determine whether your configuration
requires additional thread resources.
In addition to increasing
the size of the Default thread pool, the transport channel that handles inbound
network traffic can be configured to use a different thread pool. By default,
the transport channel uses the Default thread pool, which it shares with other
WebSphere Application Server components, including the replication service.
Creating a unique thread pool for the transport channel reduces the chances
that the replication service is not able to obtain a thread because other
components are using all of the threads that are in the pool.
See Thread pool settings
for a description of how to
change the maximum thread pool size setting.
Results
Data is replicating among the application servers in a configured
replication domain.
What to do next
If you select DES or 3DES as the encryption type for a replication
domain, an encryption key is used for the encryption of messages. At regular
intervals, for example once a month, you should go to the Environment >
Replication domains page in the administrative console, and click Regenerate
encryption key to regenerate the key. After the key is regenerated, you
must restart all of the application servers that are configured as part of
the replication domain. Periodically regenerating the key improves data security.