This document is an examination paper for a course on virtualization and cloud technology. It contains 5 questions, with students required to answer any 3 questions. Question 1 involves calculating speedup and efficiency of a parallel matrix multiplication program run on a 64-server cluster. Question 2 asks about different virtualization techniques, advantages/disadvantages of cloud computing, and impacts on HPC. Question 3 covers availability of fault-tolerant clusters. Question 4 describes cloud computing technologies and resource provisioning policies. Question 5 explains HDFS and how MapReduce achieves high throughput processing of large datasets.

1. Faculty of Science and Technology
MIDDLESEX UNIVERSITY
EXAMINATION PAPER
Academic Year 2016/2017 (April/May)
CCE4370
Virtualisation and Cloud Technology
Dr Jonathan Loo
Time allowed: 2 hours
Total number of questions: 5
Instructions to candidates: Answer any 3 questions.
Each question is worth a maximum of 25 marks.
Materials provided: None
Equipment permitted: Non-programmable calculators
Total number of pages: 6 (including front Cover)
EXAM PAPER CAN BE REMOVED FROM THE EXAM ROOM
No books, paper or electronic devices are permitted to be brought into the examination room
other than those specified above.
Candidates are warned that credit cannot be given for work that is illegible
1

2. Question 1
Consider a program for multiplying two large-scale N × N matrices, where N is the matrix size.
The sequential multiply time on a single server is T1 = cN3
minutes, where c is a constant
determined by the server used. An MPI-code parallel program requires Tn = cN3
/n + dN2
/n0.5
minutes to complete execution on an n-server cluster system, where d is a constant
determined by the MPI version used. Assume the program has a zero sequential bottleneck
(α = 0).
Answer the following questions for a given cluster configuration with n = 64 servers, c = 0.8,
and d = 0.1.
a) Using Amdahl’s law, calculate the speedup of the n-server cluster configuration for
running a fixed workload corresponding to the matrix size N=15,000.
[5 marks]
b) With reference to Part (a), calculate the efficiency of the cluster system used in Part (a)
on the n-server cluster.
[5 marks]
c) Using Gustafson’s law, calculate the speedup of the n-server cluster configuration for
running a scaled workload corresponding with an enlarged matrix size N’ = n1/3
N.
[5 marks]
d) With reference to Part (c), calculate the efficiency of running the scaled workload on
the n-server cluster.
[5 marks]
e) Compare the results in the Part a and b (fixed workload), and Part c and d (scaled
workload), and comment on their implications with respect to the speedup and
efficiency of the n-cluster configuration.
[5 marks]

3. Question 2
a) Explain the differences between hypervisor and para-virtualisation, and for each category
give an example VMM (virtual machine monitor) that was built using this approach.
[10 marks]
b) Which virtualisation technique is shown in Figure Q2? Explain its operation.
[5 marks]
Figure Q2
c) Discuss the major advantages and disadvantages (in relation to virtualisation technology)
in the following areas:
i) What breakthroughs are required to build virtualized cloud systems cost-effectively?
[5 marks]
ii) What are the impacts of cloud platforms on the future of the HPC and HTC industry?
[5 marks]

4. Question 3
a) Assume that when a node fails, it takes 10 seconds to diagnose the fault and another 30
seconds for the workload to be switched over.
i) What is the availability of the cluster if planned downtime is ignored?
[5 marks]
ii) What is the availability of the cluster if the cluster is taken down one hour per week
for maintenance, inclusive of the above mentioned repair time, but one node at a time?
[5 marks]
b) Explain the architecture and function of the following three availability cluster
configurations. Comment on their relative strengths and weaknesses.
i) Hot standby
ii) Active takeover
iii) Fault-tolerant clusters
[15 marks]

5. Question 4
a) Describe the following techniques or terminologies used in cloud computing and cloud
services. Use a concrete example cloud or case study to explain each technology listed
below.
i) Virtualized data center
[5 marks]
ii) Green information technology
[5 marks]
iii) Multitenant technique
[5 marks]
b) Describe the implications of the static cloud resource provisioning policy shown in
Figure Q4.
[5 marks]
Figure Q4
c) Discuss how a demand-drive resource provisioning policy could overcome the
implications described in Part (b).
[5 marks]

6. Question 5
a) Explain how the Hadoop Distributed File System (HDFS) is able to achieve high-
throughput access to large data sets.
[5 marks]
b) Draw a diagram to illustrate how the “word counting” problem is solved by using the
MapReduce programming model.
[10 marks]
c) Draw a diagram to illustrate how the MapReduce programming model is able to achieve
high-throughput using HDFS architecture.
[10 marks]