If a node has been out of contact with the Controller for a certain amount of time, the Controller marks the node as a historical node. The Controller suspends certain types of processing activities for the node, such as rule evaluation.

If the node resumes contact with the Controller before the node deletion period expires, the Controller restores it to an active state. Otherwise, the node is permanently removed from the Controller and the node level data is no longer accessible in the UI. Tier and application level historical metric data for the node remains available after the node is deleted.

By default, the Controller considers a node historical after about 20 days of inactivity and deletes the node after 30 days. For a highly dynamic application environment in which nodes are created and destroyed frequently, Splunk AppDynamics recommends that you shorten the node activity timeout period to allow recycled nodes to be treated as such in the Controller.

The node activity timeout period is determined by the node retention period or activity settings.

The names of historical nodes can be assigned to new nodes. Node name reuse is a Java Agent option that, when enabled, directs the Controller to reuse node names so that data generated by multiple, short-lived nodes in a given tier is associated with a single logical node.