Grafana Labs introduced Grafana Mimir, an open-source time series database (TSDB) designed to handle up to 1 billion active series, effectively addressing the increasing demand for scalable metrics monitoring solutions. Extensive load testing in 2021 led to significant optimizations in Grafana Mimir's scalability and performance, resolving challenges such as CPU utilization, compaction inefficiencies, and query execution times. Key improvements included reducing CPU usage for hash rings, enhancing the compaction process with a split-and-merge algorithm, and implementing query sharding to handle high-cardinality queries efficiently. The deployment involved a robust architecture with thousands of replicas and terabytes of memory and CPU resources, ensuring efficient data ingestion and querying. Grafana Mimir's enhancements, including asynchronous chunk writing and multi-zone rollouts, have significantly reduced latency and improved deployment consistency, making it a powerful tool for organizations dealing with extensive time series data.