title: why spark reads and writes so fast from S3
body: <p>I understand the advantage of spark in terms of processing large scale data in parallel and in-mem.</p>
  
  <p>But how does it not hit a bottleneck in terms of read/write to S3 when reading/writing data from/to S3.  Is that handled in some efficient form by the S3 storage service?  Is S3 distributed storage?  Please provide some explanation and if possible links on how to learn more about this.</p>