When using one connection, the datasource statistics show:
Available 0
Active Count 1
Max Used 1
Our application is basically the same: same actions, same frontend, same database/version (MySQL 5.0.77), same server (Centos5), same EJBs.
However, now we are using EntityManager via @PersistenceContext annotation instead of a Hibernate Session via JNDI lookup and Infinispan instead of ehcache.