使用Apache创建的空会话文件

I'm stuck on a very big problem with my session files. On the top of each php files needing an authentication I added that :

ini_set('session.cookie_lifetime', 5*3600*24*365);
ini_set('session.gc_maxlifetime', 5*3600*24*365);
ini_set('session.save_path', __DIR__.'/sessions');
session_start();

So basically I changed the sessions directory because else in /tmp, I had some issue with the garbage collector which was cleaning my sessions.

But now I have a LOT of empty session files created when users are visiting my website. When I said a lot, it reach 4 000 000 files in about one week with 30 000 unique visitors.

I'm using php 5.3.28 and Apache 2.2.26 on a Linux machine

Thank you for your help !