Configure cache replication

Use this task to improve performance by configuring the data replication service (DRS) to replicate data from the dynamic cache service across the consumers in a replication domain.

 

Before you begin

See Cache replication for more information about replicating data for the dynamic cache service.

You should have a replication domain created for the dynamic cache service. Configure a different replication domain for each type of consumer of the replication domain. For example, configure two different replication domains for dynamic cache and session manager. There are two ways to configure replication domains:

• To create replication domains manually, click Environment > Replication domains in the administrative console.

• To create a new replication domain automatically when you create a cluster, click Servers > Clusters > New in the administrative console.

For more details about configuring replication domains, see Replicating data across application servers in a cluster.

Do not use the default value of a single replica for the Number of replicas for dynamic cache replication domains. Instead, use a full group replica for any replication domains that you configure for dynamic cache.

Note: If you configured cache replication with a previous version of WebSphere Application Server, review Migrating V6.0 servers from multi-broker replication domains to data replication domains to learn about the new type of replication domains that you should use with the current version of WebSphere Application Server.

 

Overview

Use this task to improve performance in a clustered environment by enabling the data replication service (DRS) to replicate cached data across the servers in a cluster. Invalidations of cache entries are sent across the cluster to keep the cached data consistent and valid.

 

Procedure

1. In the administrative console, click Servers > Application servers > servername > Container services > Dynamic cache service.

2. To enable replication, select Enable cache replication.

3. Choose a replication domain. Use different replication domains for each type of consumer. For example, dynamic cache should use a different replication domain than session manager. The only replication domains that one can select in this panel include replication domains that are configured to use full-group replication. In a full-group configuration, every cache entry is replicated to every other cache that is configured in the servers that are in the replication domain. If none of the replication domains in your configuration meet these requirements, the list is empty. In this case, create a replication domain or alter an existing replication domain so that you have a replication domain that can perform full-group replication. See Replicating data across application servers in a cluster for more information.

4. Define the dynamic cache replication settings. Click Enable cache replication. On this page, one can define when and how often data is replicated across the dynamic cache replication domain. For more information about these settings, see Dynamic cache service settings.

5. Define sharing policies in the cachespec.xml file. We can override the global sharing policy by specifying a specific sharing policy in the cache policy. For example, if your global policy is to use Push only, one can change the sharing policy of a specific cache entry by making this change to your cache policy

   <cache-entry>
     <sharing-policy>not-shared</sharing-policy>
     <class>servlet</class>
     <name>/app</name>
     <cache-id>
       <component  type="parameter">
         <value>portfolio</value>
         <required>true</required>
       </component>
       <component id="JSESSIONID" type="cookie">
         <required>true</required>
       </component>
       <property name="EdgeCacheable">true</property>
     </cache-id>
   </cache-entry>
   

   For more information about the sharing policies that can be defined in the cachespec.xml file, see Cachespec.xml file.

 

Result

Cache entries copy to the other application servers in the configured replication domain.

 

What to do next

Use the cache monitor to view the contents of the cache. See Displaying cache information for more information.

 

See also

Cache replication

 

Related Tasks

Replicating data across application servers in a cluster
Task overview: Using the dynamic cache service to improve performance

 

See Also

Dynamic cache service settings

 

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