RRDTool is described as 'RRDtool (acronym for round-robin database tool) aims to handle time-series data like network bandwidth, temperatures, CPU load, etc. The data are stored in a round-robin database (circular buffer), thus the system storage footprint remains constant over time' and is an website in the Development category. There are seven alternatives to RRDTool, not only websites but also apps for a variety of platforms, including Linux, Self-Hosted solutions, Mac, Windows and Python. The best alternative is InfluxDB, which is both free and Open Source. Other great sites and apps similar to RRDTool are Graphite (Free, Open Source), KairosDB (Free, Open Source), OpenTSDB (Free, Open Source) and Axibase Time Series Database (Free).
ATSD is purpose-built for analyzing and reporting on massive volumes of time-series data collected at high frequency. Features include data analytics, visualization, data forecasting, reporting, alerting. All in one product built for big data.
Cube is a system for collecting timestamped events and deriving metrics. By collecting events rather than metrics, Cube lets you compute aggregate statistics post hoc. It also enables richer analysis, such as quantiles and histograms of arbitrary event sets.