The document discusses the Universitat Politècnica de València's experiences with Open edX. It provides details on UPV, including that it has 3 campuses, 13 schools, and over 36,000 students. It describes UPV's pilot phase with Open edX, including running 3 courses on it with over 4,700 total students. It discusses stress tests conducted on the Open edX infrastructure and results showing it could handle up to 1,500 concurrent sessions per hour with a database of 50,000 users. The document concludes that 1 server can handle around 50 concurrent sessions in 5 minutes and that careful synchronization is needed between application and database servers.

1. Open edX Onsite
Universitat Politècnica de València experiences
Ignacio Despujol Zabala

2. 2

3. 3

4. UPV
 Public academic
institution since 1971
 3 campuses
 13 schools
 45 research centers
 35 bachelor degrees
 58 master degrees
 30 PhD Programs
 36.000 students
 2.800 teachers
 2.600 staff
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5. MOOC Model
1 hour of video 3 hours of student work
3 hours per week of student workload
70% grade to pass
Non academic certificate
All course materials available between
editions
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6. poli[Media]
https://www.youtube.com/watch?v=-n7ODDK76WI
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7. poli[Media]
VIDEO
SCREENCAST
NON VERBAL
COMMUNICATION
+
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8. poli[Media] studio
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9. MOOCs by UPV (upvx.es)
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10. How did we start with Open edX?
 We had our courses in Google Course Builder
 They worked well, but we needed a better teacher interface and
more functionalities
 We chose OpenEdx
 We decided to start a pilot phase with some courses
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11. On premises infrastructure
VMWare ESXi 5.1
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12. App server
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13. Database server
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14. 14
Pilot phase
 3 courses using OpenEdx
 1 of them is a standard X-Mooc course
 2 courses using ORA 1.0 Module
 Enrolled and finished:
 Excel 2010: 3250;520
 Gestión participativa: 570;31
 Implantar grupos de mejora de procesos: 962;75
 TOTAL 4782;626
 Access through Course Builder main page

15. 15
Pilot phase
 Installation over Ubuntu 12.04
 2 servers in virtual machines on the same cluster
 1 server for the apps and other for the 2
databases
 We had to modify
 configuration files
 Email sending configuration
 Platform templates
 ORA and statistics file links (all S3 hosted files)
 Backup everyday
 Script for statistics in csv everyday in a network
drive

16. Pilot phase
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USERS
APPSERVER
(LMS+CMS)
MYSQL
MONGODB

17. Pilot phase – Satisfaction survey compared
Platform speed
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18. Pilot phase – Satisfaction survey compared
Platform problems
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19. Pilot phase – Satisfaction survey compared
Platform usability
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20. Pilot phase – Satisfaction survey compared
Expectations fulfilled
Average : 8,27
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21. 4th edition data
Feb 2014
14 c with Google CourseBuilder 1.0 45,639 students
3 c with Open-edX 4,790
students
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22. Concurrent sessions all courses
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1.500

23. Stress test
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24. Stress test
 Designed using Apache Jmeter
 Session recording: 1 login, 1 progress, Courseware
 Two different ramp-up periods:
 1200 seconds: 150, 300, 500 threads
 300 seconds: 50, 100, 150, 200 threads
 Matplotlib
 http://www.metaltoad.com/blog/plotting-your-load-test-jmeter
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25. Stress test – Server load
Ramp 300 s, threads 200 (1 thread every 1.5 s) 607 s test session 14:23:41-
14:38:48
App server Database server
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26. Stress test – Server load (Memory)
Ramp 300 s, threads 200 (1 thread every 1.5 s) 607 s test session 14:23:41-
14:38:48
App server Database server
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27. Stress test – Server load
Ramp 1200 s, threads 500 (1 thread every 2.4 sg) 757 s test session14:42:58-
15:15:39
27 App server Database server

28. Stress test – Server load
Ramp 1200 sg, threads 500 (1 thread every 2,4 sg) 757 sg test
session14:42:58-15:15:39
App server Database server
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29. Stress test – Results – 1200 sg
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30. Stress test – Results – 300 sg
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31. Production configuration
31
MONGO DB REPLICA SET
MYSQL
master
MYSQL
slave
Reads
Backup

32. 32
Production configuration
 Until Aspen we had problems to get exactly the same version in all
servers
 DNS Round Robin load balancing
 Server Django cache for server session vars:
'django.core.cache.backends.db.DatabaseCache‘
 Mongo Replicaset
 Theming for upvx style, spoc courses, dashboard course order,
cookies management
 server-vars.yml configuration
 Upvx-fork for user profile editing, user profile erase, mongo replicaset
connection
 Server upgrade between editions

33. OpenEdx
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34. Modifications
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35. Modifications
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36. Modifications
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37. Extensions -XNF
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38. Extensions-XNF to XML
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39. Edxtest.upv.es
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40. Extensions -Transchapter
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#python trans_chapter.py srvOrigen courseOrigen ChapterName srvDestination
courseDestination

41. Some conclusions
 1 server for apps+1 server for databases works well for
5000 enrolled students
 Max 1,500 sessions per hour with 50,000 users
 1 server can handle well 50 sessions in 5 minutes
 Servers work well in Vmware virtual machines
 App servers don’t use more than 5 GB of RAM
 Apache Jmeter is a goog tool for load tests
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42.  App server is more critical than Database server
 MySQL server is most stressed with statistics
 Careful sinchronization of servers is required
 ORA configuration and use needs careful attention
 Using an intermediate format for content creation
increases process flexibility
42
Some conclusions

43. Thanks for your attention
ndespujol@asic.upv.es