I think what they meant with "1000 nodes" is that the dataset they're using for the benchmark is synthetic monitoring data (where the thing being monitored are servers).

And the way they generated the synthetic data set is by having 1000 imaginative servers produce one sample per second, (i.e. have a script that writes out 1000 * duration_in_sec fake samples -- I believe this is the code that does it https://github.com/influxdata/influxdb-comparisons/tree/mast...)