Metrictank is a multi-tenant timeseries engine for Graphite and friends. It provides long term storage, high availability, efficient storage, retrieval and processing for large scale environments. GrafanaLabs has been running metrictank in production since December 2015. It currently requires an external datastore like Cassandra, and we highly recommend using Kafka to support clustering, as well as a clustering manager like Kubernetes. This makes it non-trivial to operate, though GrafanaLabs has an on-premise product that makes this process much easier.