I don't know why but while redis for sessions works fine for Wordpress and frameworks, both PHPMyAdmin and Cacti react badly to it. I get
Unknown: Failed to write session data (redis). Please verify that the current setting of session.save_path is correct
(tcp://127.0.0.1:6379) in Unknown on line 0" while reading response header from upstream
Again, this does not happen with the Zend/yii framework or Wordpress, so I don't know why this would not work with PHPMyAdmin or Cacti.