Capacity Service 

Automatically collects data about a cluster's operations, including Cassandra specific and platform specific (for example, disk metrics, network metrics), at both the node and column-family level (where applicable). Use OpsCenter to manage and perform trend analysis.

The Capacity Service automatically collects data about a cluster’s operations and provides for the ability to do historical trend analysis and forecasting of future trends.

For more details, see Capacity Service in the OpsCenter User Guide.