Ehcache, an open source caching solution that is included with every installation of Interact. When you enable the Ehcache solution, you can use multiple run time servers fronted by a load balancer. The load balancer balances the workload across the runtime servers in the group, and helps to maintain something called session affinity, which means that when an incoming session is handled by runtime server A, then when the same user issues additional requests, those requests are fulfilled by the session on server A. This method of balancing connections among the runtime servers in the group can improve performance considerably, but has some limitations because all of the session information is maintained in memory, and the memory limits of each Java™ virtual machine (JVM) restrict how much session information can be maintained.

Interact Extreme Scale Server, a distributed cache solution for Interact run time based on WebSphere® eXtreme Scale. This solution provides greater performance improvements for large installations than the Ehcache solution, and provides additional benefits that Ehcache does not. This is an optional installation, so contact your IBM® EMM representative for more information about acquiring this solution.