In 19.2.1. Enabling session replication in your application, Administration And Configuration Guide for EAP 5.0.1:

• There is an extra CDATA around the contents in the example jboss-web.xml
• The snapshot-mode value is lower case in the example jboss-web.xml and the subsequent details

http://www.redhat.com/docs/en-US/JBoss_Enterprise_Application_Platform/5.0.1/html/Administration_And_Configuration_Guide/clustering-http-state.html#clustering-http-app

The snapshot-mode value should be upper case, otherwise you'll get the following error at deploy:

> Caused by: org.jboss.xb.binding.JBossXBException: Failed to parse source: Invalid value instant valid are [INSTANT, INTERVAL]