... and it doesn't need that. I'm running telegraf+influx+grafana along with other services on a small rpi without issues.

Running TICK stack here collecting metrics from around a dozen different hosts (more if you count network devices like switches) to a central server with a default retention policy on spinning rust. InfluxDB process is currently sitting at 600MB RSS.

You don't need 8GB ram to run a small scale deployment of influxdb.

I'm sure this is true, but the documentation does explicitly say "Each machine should have a minimum of 8GB RAM" with absolutely no caveats about scale, so I think people can be forgiven for taking a quick look and moving on because they don't want to provision that.

That's a valid point, I've brought it up internally to improve the docs to explain what type of load this requirement is expecting. If you'd like you can create an issue for this in Github (https://github.com/influxdata/docs.influxdata.com/issues/new) to be involved in the discussion and change.

While we're working on this page, also check out https://docs.influxdata.com/influxdb/v1.8/guides/hardware_si... which gives a better breakdown of resources requirements based on expected load