Efficiently storing raw metric data in a volatile memory and aggregated metrics in a non-volatile time-series database for monitoring network elements of a software-defined network

A non-transitory machine readable medium storing a program for execution by at least one processing unit for storing operational data for network elements in a software-defined network (SDN), the program comprising sets of instructions for:

• at a metrics manager of a framework for collecting, aggregating, and storing the operational data for the SDN:
• receiving, during a particular time period, a primary set of metrics collected from at least one SDN network element, and storing the first set of metrics in a volatile memory;
• using a set of aggregation rules to aggregate the primary set of metrics into a secondary set of aggregated metrics;
• storing the secondary set of aggregated metrics in a non-volatile memory to use to monitor performance of the at least one SDN network element.