According to https://eng.uber.com/m3/
> Released in 2015, M3 now houses over 6.6 billion time series. M3 aggregates 500 million metrics per second and persists 20 million resulting metrics-per-second to storage globally (with M3DB), using a quorum write to persist each metric to three replicas in a region.
So, if that's accurate, they're collecting one trillion data points every two seconds.