XS Load Testing
Testing the OLPC School Server
Author: Benjamin Tran
Date: 12/15/2010
Abstract: The One Laptop Per Child (OLPC) project oversees the development, construction, and deployment of an affordable educational laptop (XO) for use in the developing countries. OLPC has been deployed in many countries and as of August 2010, there are over 1.85 million XO laptops in the field. The low-cost XOs help to revolutionize the way we educate the world's children. In the school, each child's XO laptop connects to a central server that provides various networking, content, and communication services. The server also acts as the Internet gateway if an Internet connection is available. The hardware capabilities of the server depend on factors such as cost of hardware and availability of electricity. A more powerful machine means faster access to data and the capability to handle more users simultaneously, but this usually implies higher power consumption, a luxury that is unaffordable in many parts of the world. The software that runs on the server in the classroom, called the School Server (XS), is based on the Fedora distribution of the Linux operating system and provides networking infrastructure, services, as well as education and discovery tools to the XO laptops. Among the stack of customized software included in the XS, one of the most noticeable collaborations tools included is Moodle. Moodle is a free web-based course management system. With the customized software running on limited hardware resources, how many users can reasonably connect to the server and use Moodle? What hardware combination would be ideal for use with the XS given the estimated total number of students in a school? The purpose of this project is to come up with a method to determine the approximate number of users a potential server loaded with the OLPC School Server is capable of supporting. The approach taken will be to perform functional and load testing against different hardware systems loaded with the School Server software. The project makes use of industry-standard technologies and tools such as Selenium, Apache JMeter, and nmon for Linux. Selenium ensures Moodle functions according to specifications while JMeter simulates various load against the server to test its capability. Nmon for Linux monitors server-side resources and presents graphs of CPU usage, free memory, and disk I/O activities among many others. Test results from six different machines are compared. The outcome of this project is a formal process to test and measure the capability of a potential server that is being considered for deployment.
Keywords: OLPC, One Laptop Per Child, XS School Server, XO Laptop, Moodle, Selenium, Apache JMeter, Software Testing, Functional Testing, Performance Testing, Load Testing, Stress Testing
This work is the result of taking course CSC895 Applied Research Project (Computer Science Department, San Francisco State University), with the guidance and assistance from the following advisors:
Professor Sameer Verma, College of Business, San Francisco State University
Professor Dragutin Petkovic, Department of Computer Science, San Francisco State University
Professor Barry Levine, Department of Computer Science, San Francisco State University
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