If you need to use different caching strategies for your Rails.cache and your ActionController::Cache (used for fragment caching) just put the following in your config/environments/env.rb file:

     config.action_controller.perform_caching = true
     # this is used for your Fragment cache
     config.action_controller.cache_store = :file_store, 'action_controller_tore_path'
     # this is used for Rails.cache
     config.cache_store = :file_store, 'cache_store_path'