This example will print out the real group id, even once the effective
group id has been changed.
<?php
echo 'My real group id is '.posix_getgid(); //20
posix_setegid(40);
echo 'My real group id is '.posix_getgid(); //20
echo 'My effective group id is '.posix_getegid(); //40
?>
Load balance : Server 01
