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
Refer to the Cache replication article 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, refer to the
Replicating data across application servers in a cluster article.
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.
Attention: If
you configured cache replication with a previous version of WebSphere® Application
Server, review the Migrating servers from multi-broker replication domains
to data replication domains article to learn about the new type of replication
domains that you should use with the current version of WebSphere Application
Server.
About this task
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
- In the administrative console, click Servers > Application
servers > server_name > Container services > Dynamic
cache service.
- To enable replication, select Enable cache replication.
- 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 you 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. Refer
to the Replicating data across application servers in a cluster article for
more information.
- Define the dynamic cache replication settings. Click Enable
cache replication. On this page, you can define when and how
often data is replicated across the dynamic cache replication domain. For
more information about these settings, refer to the Dynamic cache service
settings article.
- Define sharing policies in the cachespec.xml file.
You
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,
you 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 id="action" 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, refer to the cachespec.xml
file article.
Results
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. Refer to
the Displaying cache information article for more information.