Dell PowerConnect OpenManage Network Manager Web Client Guide 5.0 - Page 249

To reduce resource impacts, the scope of retained data may exclude some of the collected data. A monitor may have no retained data and only emit events based on transient results in the execution/calculation. For example, the application can derive a metric from several collected values and you may opt to retain only the derived result. All monitors rely on a polling engine which provides runtime mediation activities for distributed device interaction at regular intervals. Monitors may share a retention policy. Data is rolled up hourly and daily into summary data. The retention policy controls how long data is held per roll-up period. When you manage these policies, you configure how monitored data is retained. When you select Manage Retention Policies in the Monitors portlet, first a list of available policies appears. Clicking the Add button at the top of the screen lets you create a new policy, while clicking the Edit button to the right of selected, listed policies lets you modify existing policies. The Delete button to the right of listed policies removes them from the list. Resource Monitors | Monitoring 249