I'd like to followup on this and say InfluxDB is fantastic -- with the caveat that you know exactly what you want, and use it with that in mind. It's great at storing some metrics with high volume, but I've found the OSS version falls over hard in some circumstances (high cardinality in tags absolutely murders performance, making it nearly unusable).

I'm in the middle of doing a test-run of vmagent + victoria-metrics as a mostly-replacement (see: not replacing the cases where it's known exactly what's wanted, and used explicitly for that), and victoria-metrics fully support telegraf pushes which is a big bonus.

Also they're apparently going to be dropping InfluxQL entirely, for Flux, which is weird to me? The docs don't outright state this, but InfluxDB 2.0 has only Flux examples in the docs I can find. It's a better language, however the learning curve is not trivial.