title: Issue with crc32c verification using gsutil
body: <pre><code>crc32c signature computed for local file (Rgw3kA==) doesn't match cloud-supplied digest (5A+KjA==). Local file (/home/blah/pgdata.tar) will be deleted.
  </code></pre>
  
  <p>I did a bit of diagnosing, and I noticed that it was always on the cloud-supplied digest of "5A+KjA==" but usually at a different point in the file with different local crc32c. This is using either:</p>
  
  <pre><code>gsutil -m rsync gs://bucket/ /
  </code></pre>
  
  <p>or</p>
  
  <pre><code>gsutil -m cp gs://bucket/pgdata.tar /
  </code></pre>
  
  <p>I seem to get this error almost all the time transferring a large 415GB tar database file. It always exits in error at a different part, and it doesn't resume. Is there any workarounds for this? If it is legitimate file corruption, I would expect it to fail at the same point in the file?</p>
  
  <p>File seems fine as I've loaded this onto various instances and postgresql about a week ago.</p>
  
  <p>I'm not sure of the verision of gsutils, but it is the natively installed one on GCE Ubuntu 14.04 image, following the GCE provided instructions for crcmod installation on Debian/Ubuntu.</p>