I would advise activating Memcache through these changes in your Magento root folder > app > etc > env.php.

From: `'session' => array ( 'save' => 'db', )` 

In: `'session' => array ('save' => 'memcached',
'save_path' => '127.0.0.1:11211'),`

Then remove these files: `rm -rf var/cache/* var/page_cache/* var/session/*`

This will improve your website speed.