PHP will lose session data & # 8594; session files are deleted too quickly

I am stuck in a problem $_SESSIONand $_SESSIONaccidentally lost my data.

I have a form with different pages, and the user has a certain amount of time to go through all the pages.

Therefore, I set the session variable on the first page and check it on others.

start.php

 <?php
    session_start();  

    //Set Variable for Starting application
    if (!isset($_SESSION['STARTED'])){
        $_SESSION['STARTED'] = time();
    }

app_init.php

<?php
session_start();

if ((!isset($_SESSION['STARTED'])) || (time() - $_SESSION['STARTED'] > MAX_TIMELIMIT)) {
    echo '<!-- st: '.$_SESSION['STARTED'].'-->';
    // Started Variable is not set or timelimit is over.
    session_destroy();   // destroy session data in storage
    session_unset();     // unset $_SESSION variable for the runtime
    showTimeout('0');   //  show timeout
}

Beginning of pages:

<?php

// get basic settings for applications 
require_once (MODEL_PATH.'/app_init.php');

The whole system works very well on a local installation, Developmentserver and Testserver. On the Productionserver, I get a timeout at different times. It differs from 30 seconds to 10 minutes. MAX_TIMELIMITis 20 minutes. $_SESSION['STARTED']always empty in this case. In other environments, it is set correctly, even if a timeout appears after 20 minutes.

Additional Information:

• , , -.
• php.ini → session.save_path , session.cookie_lifetime 0 session.gc_maxlifetime 1440
• ( > 22 )
• URL- ( , . host/some/path/calc → host/some/path/form → host/some/path/summary → host/some/path/send
• calc, (calc, form, summary)
• php.ini . (extensions-path, session.save_path, tmp-path) .
• -
• ( $tmp session_destroy(), session_create())
• Single Frontend, Loadbalancer ( apache)
• -

:

• ( )
• (calc/form/summary)

• $_SESSION -

  array ( 'STARTED' => 1338298801, 'S_SID_' => '41554681145546', 'S_LC_' => 'de', 'version_testing' => 1, )

• 3 ( 30 ) $_SESSION:

  array ( )

• , $_SESSION, session .

• : Test/Dev , 20 .

• session.save_path ( 24 ). , . 4 .

( )
Access to Production-Server, , Session-Data 3-5 . 3 . , PHP ( GC), - , . PHP.ini , .