COSMOS Performance Testing

Introduction

Performance testing is an important part of any distributed or Web application testing, which ensures that the application delivered to a customer satisfies high load,availability and scalability requirements.

Early identification of software load limitations helps to configure the system appropriately to avoid unexpected crashes.

Some of the questions which should be addressed at system performance analysis are:

• Will the Application or Server be able to process simultaneous requests coming from hundreds, or thousands of clients ? and
• What is the frequency of requests the system can handle ?

Apache JMeter—a performance testing framework from Apache, has been widely accepted as a performance testing tool for Web applications. It can be used to analyze overall server performance under simulated heavy load.

Terminology

The terminologies/acronyms below are commonly used throughout this document. The list below defines each term regarding how it is used in this document.

Term	Definition
Scalability	Scalability refers to the ability to handle additional workload, without adversely affecting performance, by adding resources such as CPU, memory, and storage capacity.
Throughput	Throughput is the number of units of work that can be handled per unit of time; for instance, requests per second, calls per day, hits per second, reports per year, etc.
Median	Median is the number that represents the time, where half of server response time is lower than this number and half is higher
Average	Average is the total time running divided by number of requests sent to the server.
Deviation	Deviation shows how much the server response time varies, a measure of degree of dispersion, or, in other words, how spread the data are
Volume Testing	Testing which confirms that any values that may become large over time (such as accumulated counts, logs, and data files), can be accommodated by the program and will not cause the program to stop working or degrade its operation in any manner.
Load Test	A performance test focused on determining or validating performance characteristics of the product under test when subjected to workload models and load volumes anticipated during production operations
Performance Test	A performance test is a technical investigation done to determine or validate the speed, scalability, and/or stability characteristics of the product under test.
Stress Test	A stress test is a type of performance test designed to evaluate an application’s behavior when it is pushed beyond normal or peak load conditions
Response Time	Response time is the amount of time that it takes for a server to respond to a request.
Latency	In general terms, a time delay between the moment something is initiated, and the moment one of its effects begins. In the realm of software performance, latency is often referred to in the contexts of server latency, network latency and disk latency.
Utilization	In the context of performance testing, utilization is the percentage of time that a resource is busy servicing user requests. The remaining percentage of time is considered idle time.