title: Ruby: Too many open files @ rb_sysopen
body: <p>After opening a file with <code>File.new(big_file)</code> (without closing it) 1016 times (Ubuntu) or 1017 times (CentOS), it seems there is a limit and it raises:</p>
  
  <pre><code>Too many open files @ rb_sysopen - big_file (Errno::EMFILE)
  </code></pre>
  
  <p>Is there any way to raise that limit?</p>
  
  <p>On my systems, <code>ulimit</code> is set to <code>unlimited</code>.</p>