M3, a metrics platform, and M3DB, a distributed time series database, were developed at Uber out of necessity. After using what was available as open source and finding we were unable to use them at our scale due to issues with their reliability, cost and operationally intensive nature we built our own metrics platform piece by piece. We used our experience to help us build a native distributed time series database, a highly dynamic and performant aggregation service, query engine and other supporting infrastructure.