Making a Session Longer

We offer an application for our customers which allows them to log into their organization and participate in discussions, register for events and build their websites. We are using Apache 2.0.47, PHP 4.3.3 and MySQL 4.0.15 for the application. We use session cookies with PHP to establish their permissions and store other information about them while they are logged in.. The problem we are experiencing is that we are starting to have so many users on at one time that they are getting bumped off faster and faster. We have increased the MaxUsers in apache up to 1000, but that doesn¹t seem to make any difference. Our session_cookie is set to 0 in the php.ini file so there is no inherent timeout for users. We have 1.5GB of memory on our production server and aren¹t experiencing any memory swaps, so I don¹t think that is it as well. The only other possible thing I can think is that it might be related to session.gc_maxlifetime =1440 in the php.ini file. I have looked and can¹t really find much valuable information on what this really does and if it would have any affect on our sites. So, if anyone has some advise on what we can try, it sure would be greatly appreciated. Have an excellent day! Free Grafton