title: rsync backup with compression, file size differences
body: <p>I am using rsync to backup a folder regularly to another server, like this, creating a duplicate failsafe version.</p>
  
  <pre><code>rsync --partial --progress -avzl -e ssh /backup_source user@backupserver.com:/backup_dest/ &gt;&gt; /backup.log
  </code></pre>
  
  <p>I understand it uses compression when transferring the files. I've noticed some unusual differences in the destination folder's storage usage.  Depending on the command used on the destination folder, I get:</p>
  
  <p><strong>ls -lart</strong>:   returns identical list of files with filesize numbers matching between src/dest</p>
  
  <p><strong>du</strong>: returned folder size on destination is anywhere from 20-50% of the same du results on the source folder.</p>
  
  <p>If I run "du [filename]" comparison on the same file on the source/destination, the destination is once again 20-50% the size.   The contents are often text, and appear to be the same and entirely intact.</p>
  
  <p>How can I account for this file size difference? Is there some sort of compression carrying over to the destination file?  Yet how can the file appear identical in contents but take up less space?  Confused.</p>
  
  <p><strong>EDIT:</strong></p>
  
  <p>md5sum comparison of a couple files returns the same result, which is a good sign.  Still curious about "du" though.  Or a more reliable way to compare file size of a directory structure I suppose.</p>