title: Ways to achieve de-duplicated file storage within Amazon S3?
body: <p>I am wondering the best way to achieve de-duplicated (single instance storage) file storage within Amazon S3.  For example, if I have 3 identical files, I would like to only store the file once. Is there a library, api, or program out there to help implement this? Is this functionality present in S3 natively?  Perhaps something that checks the file hash, etc.</p>
  
  <p>I'm wondering what approaches people have use to accomplish this.</p>