title: How Apache AirFlow achieves scalability?
body: <p>I see that, many operators in Airflow store the data locally, before uploading it to target system. This means worker node is doing considerable amount of work, in case the data is huge.</p>
  <p>Airbnb (company who open sourced Airflow) says back in 2015 they had only 6 nodes in Airflow cluster serving 5000 jobs.</p>
  <p>Am I missing something here?</p>