Abstract: A system processes a large volume of real time hierarchical system metrics using distributed computing by stateless processes. The metrics processing system receives different types of hierarchical metrics coming from different sources and then aggregates the metrics by their hierarchy. The system is on-demand, cloud based, multi-tenant and highly available. The system makes the aggregated metrics available for reporting and policy triggers in real time. The aggregators and collectors may be upgraded to new versions with minimal loss in data.