Difference between Volume, Load and stress testing in software Testing?

Very simply we can put the difference between Volume, Load and stress testing as:

Volume Testing = Large amounts of data
Load Testing = Large amount of users
Stress Testing = Too many users, too much data, too little time and too little room

Performance Testing:

• It is  a type of non-functional testing.
• Performance testing is testing that is performed, to determine how fast some aspect of a system performs under a particular workload.
• It can serve different purposes like it can demonstrate that the system meets performance criteria.
• It can compare two systems to find which performs better. Or it can measure what part of the system or workload causes the system to perform badly.
• This process can involve quantitative tests done in a lab, such as measuring the response time or the number of MIPS (millions of instructions per second) at which a system functions.
• Why to do performance testing:

Volume Testing:

• It is a type of non-functional testing.
• Volume testing refers to testing a software application or the product with a certain amount of data. E.g., if we want to volume test our application with a specific database size, we need to expand our database to that size and then test the application’s performance on it.
• “Subjecting the program to heavy volumes of data. The purpose of volume testing is to show that the program cannot handle the volume of data specified in its objectives”
  
• The purpose of volume testing is to determine system performance with increasing volumes of data in the database.

Load Testing:

Load testing is a type of non-functional testing. A load test is type of software testing which is conducted to understand the behavior of the application under a specific expected load. Load testing is performed to determine a system’s behavior under both normal and at peak conditions.

• It helps to identify the maximum operating capacity of an application as well as any bottlenecks and determine which element is causing degradation. E.g. If the number of users are increased then how much CPU, memory will be consumed, what is the network and bandwidth response time.
• Load testing can be done under controlled lab conditions to compare the capabilities of different systems or to accurately measure the capabilities of a single system.
• Load testing involves simulating real-life user load for the target application. It helps you determine how your application behaves when multiple users hits it simultaneously.
• Load testing differs from stress testing, which evaluates the extent to which a system keeps working when subjected to extreme work loads or when some of its hardware or software has been compromised.
• The primary goal of load testing is to define the maximum amount of work a system can handle without significant performance degradation.
• Examples of load testing include: 
  • Downloading a series of large files from the internet.
  • Running multiple applications on a computer or server simultaneously.
  • Assigning many jobs to a printer in a queue.
  • Subjecting a server to a large amount of traffic.
  • Writing and reading data to and from a hard disk continuously.

Andurance(Soak) Testing:

Endurance testing is a non functional type of software testing.

• It is a type of non-functional testing.
• It is also known as Soak testing.
• Endurance testing involves testing a system with a significant load extended over a significant period of time, to discover how the system behaves under sustained use. For example, in software testing, a system may behave exactly as expected when tested for 1 hour but when the same system is tested for 3 hours, problems such as memory leaks cause the system to fail or behave randomly.
• The goal is to discover how the system behaves under sustained use. That is, to ensure that the throughput and/or response times after some long period of sustained activity are as good or better than at the beginning of the test.
• It is basically used to check the memory leaks.

Stress testing:

• It is a type of non-functional testing.
• It involves testing beyond normal operational capacity, often to a breaking point, in order to observe the results.
• It is a form of software testing that is used to determine the stability of a given system.
• It  put  greater emphasis on robustness, availability, and error handling under a heavy load, rather than on what would be considered correct behavior under normal circumstances.
• The goals of such tests may be to ensure the software does not crash in conditions of insufficient computational resources (such as memory or disk space).