OpenTSDB was built on the belief that, through HBase, a new breed of monitoring systems could be created, one that can store and serve billions of data points forever without the need for destructive downsampling, one that could scale to millions of metrics, and where plotting real-time graphs is easy and fast. In this presentation we’ll review some of the key points of OpenTSDB’s design, some of the mistakes that were made, how they were or will be addressed, and what were some of the lessons learned while writing and running OpenTSDB as well as asynchbase, the asynchronous high-performance thread-safe client for HBase. Specific topics discussed will be around the schema, how it impacts performance and allows concurrent writes without need for coordination in a distributed cluster of OpenTSDB instances.