[nani_i]

Hi fnds,

Please tell me what is Exact difference between Load Testing and Stress Testing?

Regards
Nani

[Spoorthi]

http://www.faqs.org/faqs/software-en...faq/section-15 .html

[sk_kireeti]

In a very simple a plain terms,

Testing the application with a load that application supposed to sustain as per the SRS. Here we check the performance of the application at different load levels and is acceptable or not.

Stress testing is, keeping the application under heavy loads than expected maximum loads in peak hours and checking how it affects application. This is generally done to do "failure recovery" testing.

Thanks,
Krishna

[kompella2006]

Load testing means :Gradually increase system load up to limit at what point of time system performance is fall down that can be testing
Stress test: check the system behaviour behind the limits under stress load

for example u system canbe load 100 documents that is ur system capacity then uhave to load 101 document so what is result that canbe testing

subbu

[sridhar230]

Load Testing



How well will my Web site handle the number of visitors I anticipate? Load testing is designed to verify that your site can handle the load (number of simultaneous users) you expect. The concept is simple. If you think your site will need to accommodate a certain number of simultaneous users, for instance 200 people buying the same widget at the same time using your secure credit card servers, then you would want to test for that load before putting your site into production. Actually generating a real-world load to test your site gets fairly complicated though. Each of those 200 visitors will access your site with different browsers and different versions of the same browser. They will use different machines, with different platforms. Their connections will range from 28k modem dial up to high-bandwidth data lines. Each variation that makes up the world of unique users who will visit your site has a different effect on its ability to handle the load.
At Performance Labs, we've put a lot of effort and technical innovation into being able to create real-world user loads that take into account the complexity and latency of the Internet. When we load test your site with our proven tools and methodology, you will get results you can count on, because the last thing that should create a problem with your site is an expected load.
testing an application under heavy loads, such as testing of a web site under a range of loads to determine at what point the system's response time degrades or fails.
Load Tests determine the applications behavior under load, up to and including its limits (not just at its limits). Load tests specifically refer to the load size (number of concurrent users) and related values.

Load testing identifies the volume of traffic accessing a particular application. It measures the number of simultaneous users that can successfully access the application. Load testing determines an optimum number of simultaneous users. The simplest form of load testing of allow users to logon simultaneously and navigate through the application and monitor the results. A more complex form of load testing can be performed by using an automated test tool such as LoadRunner by Mercury Interactive or QALoad by Compuware.


Stress testing

The aim of load/stress testing is to find how your web service scales as the number of clients accessing it increases. You have carried out functional and regression testing, so you know that your web service will cope with a single user. What you need to know now is if it will cope with 10, 100 or 1,000 users, or how many users it will cope with. If you double the number of users, do response times stay the same? If you double the number of servers running your web service, does its capacity double? The following section in this White Paper will go into more details about these issues.
How many simultaneous users can my site take without slowing down significantly or crashing? Stress testing is nothing more than applying a steadily increasing load to your site until it reaches the breaking point (when site performance degrades to unacceptable levels). What this test tells you is how well your site will handle unexpected loads that may come as a result of unplanned events like, changing market forces, the failure of your competitors to fill the needs of their customers, or serendipitous national publicity.
Knowing your breaking point will tell you how much excess capacity you have and give you the opportunity to create a scalability plan that will ensure a quick response when your site gets hit by a rapidly increasing load.
term often used interchangeably with 'load' and 'performance' testing. Also used to describe such tests as system functional testing while under unusually heavy loads, heavy repetition of certain actions or inputs, input of large numerical values, large complex queries to a database system, etc.

The web is one of the fastest growing technologies in the world. Companies are using web technology in the form of Internet and intranet applications to bring products and information to customers through the comfort of their desktops. Load and stress testing, a technique used in the client/server environment for years to verify reliable and timely data processing, can help determine whether web applications are accessible to potential customers in both the best and worst of times.
Typically, a client/server environment contains a client system and a server system, both of which handle a portion of an application's processing. On the web, the client is the web browser (e.g., Microsoft Internet Explorer, Netscape Navigator) and the server is the web server. The web server handles all the requests for URLs from the client, processes all server-side scripts, passes data to and from a database server, and responds to the client with HTML in the form of a web page. On more complex systems, the server environment might also include a database server, a file server, a print server and/or any other of a number of server systems. Load and stress testing in a web environment is most often concerned with the web server and possibly an accompanying database server.
Load and stress testing are mentioned in conjunction with each other, but are really two different types of tests. In the client/server environment both load and stress testing emulate multiple user operations to place a load on the server. Each user operation is a specific function performed by the system-under-test (SUT), and load is generated as multiple users invoke this operation (or series of operations) concurrently. The difference between load and stress testing is in what gets measured from the user load. In load testing, performance results are extracted based on the number of users added incrementally to the SUT. In stress testing, users are added with the sole purpose of generating server errors or even crashing the system. Simply put, load testing is used to determine how well a system will perform in a typical (and atypical) environment; stress testing is used to determine when response times become unacceptable or the system will break.
There are two methods for generating load on a server system. Both methods incorporate multiple users executing "real-world" kinds of functions. The best means to measure performance in load testing is to generate a collection of "typical" user functions (called "scenarios") performed in no particular order. Running a "typical" load creates a system environment that is level (no dips or spikes in usage) which can be scaled (or "ramped") to measure performance. The second of load testing performs stress measurements. This method utilizes "scenarios" to synchronize users to execute functions simultaneously.
When talking about "users" this normally mean real people in front of real machines interacting with their browsers (entering and extracting data through the mouse and keyboard). While there is no limit (theoretically) to the number of users available to test a system, budget and hardware constraints will limit this test scenario to a dozen users at best. Such limitations will simply not satisfy the needs of tests that require hundreds (even thousands) of users to apply the proper load. To accomplish this seemingly impossible task, there are a number of test tools on the market that automate and simulate "virtual users" (VUs) in lieu of real people
Stress testing determines the applications ability to handle large amounts of data.
Stress Testing can be much more successful with a full load applied to the server. Running addition applications on the server in conjunction with the client side tests is an additional form of stress testing.



Stress testing usually coincides with load testing. Stress testing steadily increases the load on the system beyond the maximum design load until the system fails or crashes.
The benefits of this type of testing are:
1. It tests the behavior of failures of the system.
2. It determines if system overload results in loss of data or service.
3. It also stresses the system and may cause certain defects to arise which may not normally be detected.
This type of testing can be performed informally by allowing a small user groups to logon simultaneously, then allowing another small user groups to logon within a specific time period, i.e. 20 minutes later and continue with additional user groups for a specified time period allowing the user groups will navigate through the application and monitoring the results.

Stress / Load Testing verifies that a website can handle the designed-for number of users. Usage loads and connection speeds are varied to determine average-load and peak-load performance and to determine the amount of headroom. This data is critical to the web hosting and ASP vendor who needs to perform capacity planning and provide the most cost efficient solutions to their clients

[das.testing]

One of the most common, but unfortunate misuse of terminology is treating "load testing" and "stress testing" as synonymous. The consequence of this ignorant semantic abuse is usually that the system is neither properly "load tested" nor subjected to a meaningful stress test.

1. Stress testing is subjecting a system to an unreasonable load while denying it the resources (e.g., RAM, disc, mips, interrupts, etc.) needed to process that load. The idea is to stress a system to the breaking point in order to find bugs that will make that break potentially harmful. The system is not expected to process the overload without adequate resources, but to behave (e.g., fail) in a decent manner (e.g., not corrupting or losing data). Bugs and failure modes discovered under stress testing may or may not be repaired depending on the application, the failure mode, consequences, etc. The load (incoming transaction stream) in stress testing is often deliberately distorted so as to force the system into resource depletion.

2. Load testing is subjecting a system to a statistically representative (usually) load. The two main reasons for using such loads is in support of software reliability testing and in performance testing. The term "load testing" by itself is too vague and imprecise to warrant use. For example, do you mean representative load," "overload," "high load," etc. In performance testing, load is varied from a minimum (zero) to the maximum level the system can sustain without running out of resources or having, transactions suffer (application-specific) excessive delay.

3. A third use of the term is as a test whose objective is to determine the maximum sustainable load the system can handle. In this usage, "load testing" is merely testing at the highest transaction arrival rate in performance testing.[/B]

[phanindrasai boyapati]

stress testing is testing the product beyond the limits os load testing.

load testing is testing done to the srs document standards

[tejus]

load testing: testing the sever or cpu under customer expected load or value
stress testing: testing the server or cpu under max load or peak load.

[shailaja.kishore]

Originally Posted by nani_i

Hi fnds,

Please tell me what is Exact difference between Load Testing and Stress Testing?

Regards
Nani

hi,
load testing means testing the application to determine whether the system is able to handle the various anticipated load performed under different concurrent users.
stress testing means stressing the application beyond the anticipated load to determine at what point application performance degradeing or crashing point.this is the one step beyond the load testing limit.understood.
shailajakishore