Magento 1.7.0.2 External Full Page Cache

[dandrikop]

I have Magento 1.7.0.2 and I have some questions about the settings found at System > Configuration > ADVANCED > System > External Full Page Cache Settings:

• Is Magento's built-in External Full Page Cache related with the below code block at /app/etc/local.xml file?

<full_page_cache>
   <backend_options>
      <cache_dir>full_page_cache</cache_dir>
   </backend_options>
   <slow_backend_options>
      <hashed_directory_level>1</hashed_directory_level>
      <hashed_directory_umask>0777</hashed_directory_umask>
      <file_name_prefix>fpc</file_name_prefix>
      <cache_dir><![CDATA[full_page_cache]]></cache_dir>
   </slow_backend_options>
</full_page_cache>

• If the above code of /app/etc/local.xml file is NOT related with Magento's External Full Page Cache, at which cases this code should be added at the file /app/etc/local.xml?
• Which is the location of the cache_dir = full_page_cache as declared in this code? I didn't find anything under Magento's /var or /var/cache directories.
• What's the difference between Magento's built-in External Full Page Cache and the Full Page Cache extensions offered by some Magento developing companies?

[kgerasimov]

This feature uses Zend Page Cache. If you're not on Zend Server it does nothing.

More info - https://magento.stackexchange.com/questions/29513/mage-pagecache-external-full-page-cache