Because nodes send metrics and aggregated events to the shared cache, they are not sent to CentraSite immediately after a Web service is invoked. This is because the senior node only scans the list of events and metrics in the shared cache at a predefined 15-second interval, called a tick interval.

In addition, you configure the policy actions and metrics reporting tasks to run at their own particular interval (in minutes) as follows:

While the tick interval determines how often the senior node scans the list of policy actions and metrics in the stored cache, the policy actions and metrics cannot be processed until the time interval for each has been met. For example, if the policy interval for metrics reporting is configured to run every 10 minutes, then the senior node processes metrics every 40 tick intervals. This is because there are 4 tick intervals every minute for 10 minutes: so it takes 40 tick intervals before the 10-minute policy interval for the metrics is reached (4 * 15 seconds * 10 = 10 minutes). At that time, the senior node can send a processing event to the nodes in the cluster and the responding node reports the metrics to CentraSite.