Configuring Non-Sticky Sessions

This section describes the configuration of non-sticky sessions

Overview: Why Use Non-Sticky Sessions?

Some situations require that sessions be ‘non-sticky’, which means that client requests are directed to any server in a cluster of application servers rather than returning to the same server with each request for a given client. Non-sticky sessions allow for more effective load balancing as a client operating in a model using sticky session replication will return to the same server each time regardless of load. To achieve a non-sticky session model, you must configure your deployment as described for the following modules/topologies.

Note: Non-sticky sessions affect performance because sessions need to be re-created every time a request hits a different server. This may not be noticeable when the session attributes are small, but may become more evident as the session attributes increase in size and/or number.

Configuring Non-Sticky Session Replication for Tomcat and TC Server

Peer-to-Peer

For peer-to-peer topologies, apply the following settings to enable non-sticky sessions to work correctly:

• Java system property gemfire.loadClassOnEveryDeserialization=true. Set this property by editing the bin/setenv.sh file.
• prefer.deserialized.form=false. Set this property in conf/catalina.properties.

Client-server

• The Java system property gemfire.loadClassOnEveryDeserialization=true must be set, in the bin/setenv.sh file.
• The local client cache must be empty. Ensure that the gemfire.cache.enable_local_cache property is set to false. This effectively sets the local client cache to be a PROXY cache.
• If the local client cache is a PROXY cache, then expiration must be configured to notify the client via callback, which can be done by setting gemfire.EXPIRE_SENDS_ENTRY_AS_CALLBACK to true. This allows the client cache to retrieve and expire the actual session object, resulting in more consistent behavior.

Configuring Non-Sticky Session Replication for WebLogic

Peer-to-Peer

No additional configuration is required.

Client-Server

• The local client cache must be empty. Ensure that the gemfire.cache.enable_local_cache property is set to false. This effectively sets the local client cache to be a PROXY cache.
• If the local client cache is a PROXY cache, then expiration must be configured to notify the client via callback, which can be done by setting gemfire.EXPIRE_SENDS_ENTRY_AS_CALLBACK to true. This allows the client cache to retrieve and expire the actual session object, resulting in more consistent behavior.