[jboss-cvs] JBossAS SVN: r84592 - projects/docs/community/5/Clustering_Guide/en-US.

[jboss-cvs-commits at lists.jboss.org]

Author: bstansberry at jboss.com
Date: 2009-02-21 09:24:29 -0500 (Sat, 21 Feb 2009)
New Revision: 84592

Modified:
   projects/docs/community/5/Clustering_Guide/en-US/Clustering_Guide_Introduction.xml
Log:
General edits

Modified: projects/docs/community/5/Clustering_Guide/en-US/Clustering_Guide_Introduction.xml
===================================================================
--- projects/docs/community/5/Clustering_Guide/en-US/Clustering_Guide_Introduction.xml	2009-02-21 14:11:56 UTC (rev 84591)
+++ projects/docs/community/5/Clustering_Guide/en-US/Clustering_Guide_Introduction.xml	2009-02-21 14:24:29 UTC (rev 84592)
@@ -395,8 +395,8 @@
          <section id="clustering-quickstart-ejbsessions">
            <title>EJB Session Bean Clustering Quick Start</title>
            <para>JBoss AS supports clustered EJB session beans, whereby
-           requests for a bean are balanced across the cluster, and, for
-           stateful beans, a backup copy of bean state is maintained on one
+           requests for a bean are balanced across the cluster. For
+           stateful beans a backup copy of bean state is maintained on one
            or more cluster nodes, providing high availability in case the
            node handling a particular session fails or is shut down. Clustering
            of both EJB2 and EJB3 beans is supported.
@@ -446,6 +446,7 @@
            of database reads. You should always load test your application
            with second level caching enabled and disabled to see whether
            it has a beneficial impact on your particular application.</para>
+           
            <para>If you use more than one JBoss AS instance to run your 
            JPA/Hibernate application and you use second level caching, you must 
            use a cluster-aware cache. Otherwise a cache on server A will still 
@@ -496,6 +497,15 @@
            <para>See <xref linkend="clustering-entity"/> for more advanced 
            configuration options and details on how to configure the same
            thing for a non-JPA Hibernate application.</para>
+           
+           <note><para>Clustering can add significant overhead to a JPA/Hibernate 
+           second level cache, so don't assume that just because second level 
+           caching adds a benefit to a non-clustered application that it will be 
+           beneficial to a clustered application. Even if clustered second level 
+           caching is beneficial overall, caching of more frequently modified
+           entity types may be beneficial in a non-clustered scenario but not in
+           a clustered one.  <emphasis>Always</emphasis> load test your application.
+           </para></note>
          </section>
          
       </section>