The ATG platform implements a session backup facility that allows you to specify a set of session-scoped Nucleus components and properties that should be backed up after every request. This session backup mechanism saves these components and properties, and restores them when the application server migrates a session to another server.
ATG’s component backup works with your application server’s persistence facility. To use backup, you must be running your application server in a cluster, and you must enable its in-memory replication form of session persistence for each ATG application (see your application server documentation for information). Note that when you enable in-memory replication for an application, that application must not be deployed on any application server that is not part of a cluster.
To enable ATG’s backup, set the backingUpSessions property to true in the /atg/dynamo/Configuration.properties file in the localconfig layer.
backingUpSessions=true
By default, the user’s profile and shopping cart (if one exists) are backed up. To back up additional session-scoped components, set the sessionBackupServerPropertyList property in the /atg/dynamo/Configuration.properties file to a comma-separated list of Nucleus component properties. For example:
sessionBackupServerPropertyList+=\
/atg/userprofiling/ProfileFailService.uidForFailover,\
/atg/dynamo/security/UserFailService.savedPersonae
Keep in mind when backing up additional information that the more you back up, the more data the app server must save, which could affect performance.
Each component or property specified in sessionBackupServerPropertyList must implement java.io.Serializable (or Externalizable). If a component is listed without any properties, the entire component is backed up.
