Thanks for the reply and suggestion. But, I don't think the ONLINE User blocks working properly. I have refresh my browser. Should I also clear my cookie? or temporary internet file? I can use the maintenance mode. But it will not work, because I really need to down the server, and I don't want user to lost anything before I shutdown.
I have also done some testing using Apache JMeter for 50 users. I have tested 50 users Login and log off from Moodle. Then, refresh my browser, and all the 50 users display under Online User blocks, and I need to wait for 15 mins for it to disappear.
I agree that HTTP is stateless. As long if the user has not click log out, it will treated as Online even though they do nothing.
But at least the ONline block should able to check if the user session has already after log out, then it should remove it from the list. I have used the news and announcement for the broadcast. But, I think it will still the best if we can do broadcast with small alert windows to tell the users to log out.
Creating an ajax script may solve the problem, as you it may increase the server load.
Has anyone else having the same problem and find the solution?
Thanks and Best Regards,