Cost efficiency is an often mentioned strength of cloud computing. In times of decreasing educational budgets virtual labs provided by cloud computing might be an interesting alternative for higher education organizations or IT training facilities. This contribution analyzes the cost advantage of virtual educational labs provided via cloud computing means and compare these costs to costs of classical ed- ucational labs provided in a dedicated manner. This contribution develops a four step decision making model which might be interesting for colleges, universities or other IT training facilities planning to implement cloud based training facilities. Furthermore this contribution provides interesting findings when cloud computing has economical advantages in education and when not. The developed four step decision making model of general IaaS applicability can be used to find out whether an IaaS cloud based virtual IT lab approach is more cost efficient than a dedicated approach.

1. Nane Kratzke
ARE CLOUD ENABLED VIRTUAL
LABS ECONOMICAL?
A Case Study Analyzing Cloud Based Virtual
Labs for Educational Purposes
Prof. Dr. rer. nat. Nane Kratzke
1
Computer Science and Business Information Systems

2. Introduction
These use cases (among others ) are postulated to be cloud compatible
data storage,
support software short-term system disaster recovery
hosting websites
development cycles demonstrations and business
continuity
overflow processing
Training and media processing or large-scale
educatioin and rendering scientific data
processing
• Research shows that cost advantages of cloud
computing are deeply use case specific
• Be aware of comparing non comparable use cases
• This contribution analyzes the cost advantage of
virtual educational labs provided via cloud computing
means
Prof. Dr. rer. nat. Nane Kratzke
2
Computer Science and Business Information Systems

3. The next 30 minutes are about ...
• Definition of virtual labs
• Analyzed use case
• Some use case specific findings about costs
• Some use case specific findings about ressource usage
• Decision making is not always obvious => How to decide?
• Findings and advices
• Establishing virtual labs
• Is the concept transferable?
• Advices for practical courses
• Pragmatic rules for cost control
• Conclusion and outlook
Prof. Dr. rer. nat. Nane Kratzke
3
Computer Science and Business Information Systems

4. What is a virtual lab (definition)
A Virtual Lab is a collection of
compute, storage and networking
resources provided by an
educational organization for
educational or research purposes.
It can be provided to a single or a
small group of students.
Provided resources are available for
short-term use and are billed by
actual resource consumption.
In most of the times provided
resources are rented by the
educational organization from a
cloud service provider.
Prof. Dr. rer. nat. Nane Kratzke
4
Computer Science and Business Information Systems

5. Analyzed use case
• Web technology lecture/practical course for 49 computer science students
in summer 2011.
• Project 1: Develop a website for a scientific conference on robotic sailing
• Project 2: Google map based automatic sailbot tracking service
• All groups were assigned cloud service accounts provided by Amazon Web
Services (AWS).
• Analysis of billing as well as usage data provided by AWS.
Prof. Dr. rer. nat. Nane Kratzke
5
Computer Science and Business Information Systems

6. (A)
Costs per Month (aligned to Weeks)
500
Cost analysis
400
Costs in USD
300
200
Total costs: 846.99 $
100
Total students: 49
Cost per student: 17.28 $
0
CW 13 CW 14 – CW 17 CW 18 – CW 21 CW 22 – CW 25
Calendar Weeks (CW)
(B)
Main Cost Drivers
instancehour (62%)
Main identified cost drivers:
(1) Server uptime (2/3)
datatransfer (0%)
adressing (3%)
(2) Data storage (1/3)
datastorage (34%)
Prof. Dr. rer. nat. Nane Kratzke
6
Computer Science and Business Information Systems

7. 0
13 14 15 16 17 18 19 20 21 22 23 24 25
Average to Peak Ratio per Week (I)
Calendar Week
(C)
Average Box to Maximum Box Ratio
according to Weinman
1.0
Cloud computing is
economical not reasonable
Avg to Max Box Usage Ratio
0.8
Cloud computing
0.6
might be reasonable
0.4
Cloud computing is
0.2
economical reasonable
0.0
14 16 18 20 22 24
Calendar Week
Prof. Dr. rer. nat. Nane Kratzke
7
Computer Science and Business Information Systems

8. 0
13 14 15 16 17 18 19 20 21 22 23 24 25
Average to Peak Ratio per Week (II)
Calendar Week
(C)
Average Box to Maximum Box Ratio
according to Weinman
1.0
Training
Cloud computing is
Project 24x7
economical not reasonable
Avg to Max Box Usage Ratio
0.8
Cloud computing
0.6
might be reasonable
0.4
Migration
Cloud computing is
0.2
economical reasonable
0.0
14 16 18 20 22 24
Calendar Week
Prof. Dr. rer. nat. Nane Kratzke
8
Computer Science and Business Information Systems

9. Economical Decision Analysis
A four step process to decide for or against cloud based virtual labs
(A)
Determine your atp Maximum and Average Box Usage
50
ratio Average Box Usage
Maximum Box Usage in an hour
40
Used Server Boxes
30
Determine your
20
dedicated costs
10
0
13 14 15 16 17 18 19 20 21 22 23 24 25
Calendar Week
Determine your
(B)
maximal cloud costs Max instances: 49 2000 Accumulated Processing Hours per Week
Processing hours: 7612
1500
Processing Hours
Determine appropriate
Average: 7612 / (26 * 7 * 24) = 1.74
1000
cloud ressources Overall atp ratio: 1.74 / 49 = 0.035
500
Prof. Dr. rer. nat. Nane Kratzke
9
0
Computer Science and Business Information Systems
13 14 15 16 17 18 19 20 21 22 23 24 25

10. Economical Decision Analysis
A four step process to decide for or against cloud based virtual labs
Determine your atp According to Weinmann the peak-to-average
ratio ratio should be greater than the relation
between the variable costs c and the
dedicated costs d:
Determine your
dedicated costs
Example Server: 500 US Dollar
Determine your
maximal cloud costs Amortization: 3 years
500$
Determine appropriate
d5years (500$) = = 0.019 $ h
3 • 365 • 24h
cloud ressources
Prof. Dr. rer. nat. Nane Kratzke
10
Computer Science and Business Information Systems
€

11. Economical Decision Analysis
A four step process to decide for or against cloud based virtual labs
Determine your atp
ratio
Determine your
dedicated costs
Determine your
maximal cloud costs
0.019 $ h $
c Max = = 0.54
Determine appropriate
0.035 h
cloud ressources
Prof. Dr. rer. nat. Nane Kratzke
11
€ Computer Science and Business Information Systems

12. Economical Decision Analysis
A four step process to decide for or against cloud based virtual labs
Determine your atp 0.023 $ h $
ratio c Max = = 0.54
0.035 h
Pricings for EU region, 19th March, 2012
Determine your €
Example: Amazon Web Services EC2-
dedicated costs
Determine your
maximal cloud costs
Determine appropriate
cloud ressources
Prof. Dr. rer. nat. Nane Kratzke
12
Computer Science and Business Information Systems

13. General Findings
• Cloud computing loves peak load scenarios (higher
education provides peak loads, be happy)
• Cloud generated costs are use case specific (be
carefull)
• Main cost drivers are (try to minimize)
• Box usage (server uptime)
• Data storage (server volumes)
• Not economical interesting use cases (try to avoid)
• 24x7 and
• constant loads
Prof. Dr. rer. nat. Nane Kratzke
13
Computer Science and Business Information Systems

14. Transferability
According to module descriptions of computer science (near) study
programs of the Lübeck University of Applied Sciences
• Industrial Networks and
Databases
• Informationtechnology
• Databases
common:
Ressource requirements in
• Integrated • Database
Informationsystems • Distributed
• Distributed Systems processing instances
• Operating Systems • Webtechnologies
• ... • Linux/Unix based
instances
• Parallel processing
Whenever there exist a practical
• Large-scale data
course with one of the mentioned
processing
ressources requirements a virtual lab
might be a reasonable option.
Prof. Dr. rer. nat. Nane Kratzke
14
Computer Science and Business Information Systems

15. Advices
#1 • Initial training phase (may be even an
virtual lab training course)
#2 • Cloud computing gives flexibility. Use it! No
presence is required (after initial training)
#3 • Watch your costs and establish a cost
awareness
Prof. Dr. rer. nat. Nane Kratzke
15
Computer Science and Business Information Systems

16. Mindkeeping cost control rules for
students
motivation rule
Prof. Dr. rer. nat. Nane Kratzke
16
Computer Science and Business Information Systems

17. Conclusions
• Cloud based labs are scalable (10, 100, 1000
students)
• Decision making must not be obvious => four step
decision making model
• Analysed use case showed a 25 to 50 times cost
advantage in comparison to classical dedicated
approaches
• advices for applying virtual labs in practical courses
• common requirements to search for similar courses
• It is likely that cloud based virtual labs might be
an economical option for several practical
courses, but ...
Prof. Dr. rer. nat. Nane Kratzke
17
Computer Science and Business Information Systems

18. Outlook
• Provided cloud management tools are not
designed for educational purposes so far
• Missing multi account handling
• Missing cross region handling
• Missing comfortable batch processing of
recurring administrational tasks
• Our focus: Management software to set
up and manage virtual labs
• Reduce administrational efforts for teachers
• Automatic average to peak ratio calculation
• Decision support by analysing generated
usage as well as cost data
Prof. Dr. rer. nat. Nane Kratzke
18
Computer Science and Business Information Systems

19. Thank you for listening
You can find this presentation here:
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Prof. Dr. Nane Kratzke
Computer Science and LinkedIN:
Business Information Systems nanekratzke
Lübeck University of Applied Sciences
Mönkhofer Weg 239 WEB:
23562 Lübeck Mail:
kratzke@fh-luebeck.de http://praktische-informatik.fh-luebeck.de
Germany
Prof. Dr. rer. nat. Nane Kratzke
19
Computer Science and Business Information Systems