Hi this is my fourth part of the Tomcat Clustering Series . In this post we are going to discuss the how to setup session replication using Backup Manager in tomcat clustering environment. Session replication makes High availability and full fail-over capability to our clustering environment. [Check the video below for better understanding] Its continuation of the last post (session replication using Delta Manager) . In delta manager each tomcat instance need to replicate the session information to all other tomcat instances. Its take more time and replication if our cluster size is increased. so there is alternative manager is there. Its Backup Manager. Backup Manager is replicate the copy of session data to exactly one other tomcat instances. This big difference between both managers. here which tomcat creates that is primary copy of the session. and another tomcat whose hold the replicate session is backup copy . If any one of the tomcat is down....