User session replication

Do not attempt to replicate sessions across PolicyCenter cluster members. PolicyCenter does not implement or support user session replication for a number of reasons, including the following:

• PolicyCenter sessions are not serializable. Therefore, you cannot replicate a PolicyCenter session, either with or without persistence to the database.
• PolicyCenter sessions hold the user state in memory and contain large amounts of information. Guidewire estimates that this information amounts to 1 MB of data on average for a 32-bit server and close to 2 MB for a 64-bit server. Session replication would create significant cross-member communication that is detrimental to performance.
• PolicyCenter commits changes to the database on almost all transactions. Notable exceptions are some wizards for which PolicyCenter commits data changes only after the user completes all necessary entries.
• PolicyCenter scales horizontally almost linearly. The implementation of a session replication solution would very likely impede that linear scalability.

Instead, Guidewire recommends that you implement a PolicyCenter cluster consisting of multiple PolicyCenter application instances with failover and a load balancing solution. The load balancer must implement session affinity, meaning that it must route connections from the same user session to the same PolicyCenter server.