protected function init() {		
	    if(Apc::isAvailable()) {
		    $driver = new Apc();
		} else {
			if (!is_dir(WT_DATA_DIR.DIRECTORY_SEPARATOR.'cache')) {
				// We may not have permission - especially during setup, before we instruct
				// the user to "chmod 777 /data"
				@mkdir(WT_DATA_DIR.DIRECTORY_SEPARATOR.'cache');
			}
			if (is_dir(WT_DATA_DIR.DIRECTORY_SEPARATOR.'cache')) {
			    $driver = new FileSystem(array('path' => WT_DATA_DIR.DIRECTORY_SEPARATOR.'cache'));
			} else {
				// No cache available, let's just use a basic one :-(
				$driver = new Ephemeral();
			}
		}		

		$this->cache = new \Stash\Pool($driver);		
		$this->is_init = true;
	}