Abstract: A system, methods, and apparatus are provided for performing capacity planning within a system that experiences high volumes of data having high velocity and high variability. Based on historical traffic, a forecast is generated for one or more relatively coarse time periods (e.g., weeks, days), and is decomposed to yield finer-grained forecasts (e.g., for hours, minutes) by applying a distribution index also generated from historical traffic. Estimated replication latency for the forecast period can be calculated from the traffic forecast and an expected level of replication capacity. Further, a required amount of replication capacity can be determined based on a traffic forecast and a maximum replication latency permitted by a service level agreement (SLA) of an event consumer. In addition, replication headroom can be computed, to identify a maximum level of traffic that can be sustained without violating an SLA and/or a date/time at which a violation may occur.