Group 1: 160 students (4 rooms)
- teacher started up IE6 and Moodle site remotely, up to the Moodle login screen on all 160 computers. perhaps 2-3 minutes to load.
- students logged in (I had pre-enrolled them and prepared login cards for them to copy) Problems started here. Long delays.
- students clicked on the course link and long delays. 10 minutes to get to test page for some. Most could not get anything. About 20% got an error screen that said something about a database problem. No one even got into the test.
- a computer center assistant standing by thought it might be an Apache setting limiting the number of users. We ran to the server and changed the Apache setting of max clients from a default of 150 up to 1000. This seemed to help some students a little but still only 2 students could actually get into the quiz after 30 minutes of trying.
- we decided to let the students go, and decided to give them the test on paper the following week.
- we cleared the rooms, and got ready for the next group.
Group 2: 80 students (2 rooms)
- teacher started up IE6 and Moodle site again remotely, but the remote software did not work in one room, so we tried to do it manually on those computers.
- students logged in with less delay
- 40 students could open the test and began the quiz before the other students. Some delays in the audio so we told them to jump ahead to the reading section of the test (no audio).
- second room started the test 10 minutes later and had longer delays in opening the test.
- audio problems started popping up. Some students could hear only 25 out of 30 audio clips. Some could hear all, some could hear all but one. They started sharing headphones to hear the missing clips
- on some computers a popup screen appeared asking if the student wanted to enable Flash on their computer. If the answered Yes, no problem. The few that answered No, got problems with the Flash player icons appearing. An odd graphic appeared that could not be played.
- Finally, by going 10 minutes overtime, all 80 students could finish and score their tests. Success!
- 11 of the 80 scores however were listed under the ID of the students in the previous group. All of those were in the room where we could remotely restart all the browsers. We believe the browsers were not closed and restarted on those 11 students.
- Later that day, my programmer friend found another setting problem...in MySQL the maximun connections were limited to only 100. He said...
(when you start mysql, you can use some option parameters.
e.g. # /usr/local/mysql/bin/safe_mysqld --user=mysql
Server Setup: Mac OS X 10.3.3 on a Power Mac 933mhz with 768MB Ram
Apache 1.3.29 (standard Mac build), PHP 4.3.2 (no GD working), MySQL 3.23.49
Student Client Setup: PCs running Windows 2000Pro, IE6 browsers, Flash 7 installed.
1. Set Apache max clients=1000
2. Set MySQLmax connections=1000
3. Add a php accelerator (server logistics version of PHP 4.3.4 includes MMCache)
4. Add memory to over 1GB
5. Upgrade CPU to Mac Dual 1.2ghz
6. Move to Server Logistics Apache2-PHP4.3.4-MySQL4-MMCache package
7. Run the test so that each room starts a few minutes apart (avoid huge jam of requests)
8. Keep a paper version of the test handy in case of disaster
1. Will the above plan fix the problem? Will we be able to handle a load of 200 simultaneous users doing the above audio-quiz?
2. Are other problems, settings that we missed? How can we fine tune the setup to improve performance?
3. Is Apache 2 no problem?
4. Was the embedded audio problem due to the server problems? Or do we still have some resource permission problem? Why did only a few audio clips not play?
5. Any other suggestions?