OpenTSDB is a distributed, scalable time series database built on top of Apache HBase. Designed specifically to handle large volumes of time series data from various sources, it enables users to collect, store, and serve vast quantities of metrics with high efficiency and reliability. OpenTSDB is particularly well-suited for monitoring and analyzing operational data in real-time, making it a popular choice for infrastructure monitoring, IoT data analytics, and more. Its architecture allows for seamless scaling and high availability, while offering a rich set of features including data retention policies, aggregation functions, and a RESTful API for easy interaction and integration.