title: What's the benefits of "svn:externals"?
body: <p>I would not get to know svn:externals if I haven't run into the <a href="http://www.symfony-project.org/getting-started/1_4/en/03-Symfony-Installation" rel="nofollow noreferrer">this page</a>. So, I setup my  working folder. Then</p>
  
  <pre><code>mkdir lib/vendor
  svn add --parents lib/vendor
  svn ps svn:externals 'symfony http://svn.symfony-project.com/branches/1.4/' lib/vendor/
  svn ci -m "add externals"
  svn update
  </code></pre>
  
  <p>The "svn update" enlists the whole symfony folder and is pretty slow. I thought that would be single time pain. However, SVN will check external repository every time I typed "svn up". I have to use --ignore-externals to make "svn update" fast enough.</p>
  
  <p>I'm wondering what's the benefits of svn:externals if it is so slow. I'd rather copy symfony to my own repository, which is surely a faster solution.</p>