A persistence resource configuration is contained in a <persistence-resource> element.
This element must have a name attribute, which specifies the name of the persistence resource.
The name must be unique between all persistence resource configurations.
A <persistence-resource> element may also include zero or more <persistence-instance-ref> elements.
Each <persistence-instance-ref> element must have a name attribute, which must be the name of a persistence instance defined elsewhere in the configuration file.
The persistence resource will store relevant in-memory database state into each referenced persistence instance.
Example
Below is an example of a persistence resource that stores state into two PostgreSQL databases:
<persistence-resource name="management">
<persistence-instance-ref name="postgres-db1"/>
<persistence-instance-ref name="postgres-db2"/>
</persistence-resource>
