title: What exactly does the Memcached size limit represent with file system entitystore?
body: <p>Good afternoon,</p>
  
  <p>I have Memcached hooked up in my app on Heroku.  The limit for the free managed plan is 5MB for Memcached and 25MB for Memcachier.  Being new to pretty much everything, I was just hoping for clarification of exactly what this represents.</p>
  
  <p>I have the DalliStore set up in my config file, and the typical options set up for Rack::Cache.  My metastore is in Memcache and the entitiy store is set up on the filesystem.</p>
  
  <p>Questions:</p>
  
  <ol>
  <li>Does this mean that my 5/25MB limit is only being used by the meta information that I am storing about each cache fragment?  This would mean that I'd be able to store a ton of information on just the free plans?</li>
  <li><p>What exactly is the breakdown / story between Rack::Cache and Memcache (via Dalli store?)  Do they serve different purposes?  Are they doing the same thing?  i.e. is the following code redundant </p>
  
  <p><code>config.cache_store = :dalli_store</code></p></li>
  </ol>
  
  <p>and</p>
  
  <pre><code>config.action_dispatch.rack_cache = {
    :verbose      =&gt; true,
    :metastore    =&gt; Dalli::Client.new,
    :entitystore  =&gt; 'file:tmp/cache/rack/body',
    :allow_reload =&gt; false
  }
  </code></pre>