Website crashing, only fixed by clearing session files

I had this problem.
Some shared hosting disables automatic garbage collection.
On my server, session.gc_probability is set to 0.
There is a server CRON job in place to remove garbage. However, this will never find the files CodeIgniter has created.

You have to set ini values for
session.gc_probability and session.gc_divisor

In my /common.php I placed the following

Code:

// enable garbage collection
ini_set('session.gc_divisor', 10);
ini_set('session.gc_probability', 1);