title: Redshift unload to S3 is extremely slow
body: <p>I'm using a ds2.xlarge Redshift cluster in US West with about 1TB of data. I'm trying to UNLOAD a 50GB table to an S3 bucket in the same region as follows:</p>
  
  <pre><code>UNLOAD ('select * from table_name') TO 's3://bucket/folder_name/'
  CREDENTIALS 'aws_access_key_id=foo;aws_secret_access_key=bar'
  MANIFEST;
  </code></pre>
  
  <p>This query takes about 1 hour to run. This seems surprising since the Amazon website says that we'll have an I/O of 0.5GB/s for our cluster, which means the 50GB table should take less than 2 minutes to be uploaded to S3, not an hour. (20-30x times slower than advertised)</p>
  
  <p>Has anyone else run into this issue and/or found a fix / workaround? If we decide to use Redshift, we will need to move about 200GB of data from Redshift to S3 every day.</p>