strange session problem

Hi there, I have multiple web servers all running PHP 4.2.3, and they all have the same domain name implemented by round robin DNS. And I use a NFS filesystem, /home/share/tmp, for session.save_path. The main purpose is when my web clients move from one server to the others, the session will remain the same. But I've encountered an unknown problem: sometimes the session data will be lost and my client is kick out. I've checked my php.ini settings, and even I change session.gc_maxlifetime to 86400 the problem remains. Am I doing the wrong way? Or is the session functions still buggy? Eddie Lien R&D Department UUSS Technology, Inc./Taiwan Tel: +886-2-2609-6898