Stress Testing Repository: Websites & Computers

The following is an article on performance testing by LoadStorm.

"So far in our series of Web Performance articles, we've addressed the three majors types of caching that Web server application developers can employ: server file caching, application caching, and data caching
We've looked at additional performance enhancements that Web server administrators can can activate, such as HTTP compression, file consolidation, and connection pipelining.

In this latest installment of our series, we're going a little deeper and focusing on Apache. The world's most popular Web server, Apache currently powers over 63% of sites on the World Wide Web. While Apache runs decently out of the box, development teams and system administrators should combine frequent load-testing with one or more of the following recommendations to ensure their applications remain responsive under high load.

Memory Models: Prefork vs. Worker
A Web server must be able to respond to anywhere from dozens to thousands of concurrent user requests. Each request, obviously, must be fulfilled by either a separate application process, or a separate thread running within a single process.

The following article is about performance testing from Dan Goodin in San Francisco.

"Maintainers of the open-source Apache webserver are warning that their HTTP daemon is vulnerable to exploits that expose internal servers to remote attackers who embed special commands in website addresses.

The weakness in 1.3 and all 2.x versions of the Apache HTTP Server can be exploited only under certain conditions. For one, they must be running in reverse proxy mode, a setting often used to perform load balancing or to separate static content from dynamic content. And even then, internal systems are susceptible to unauthorized access only when certain types of reverse proxy rewrite rules are used.

Nonetheless, the vulnerable reverse proxy configurations are common enough that Apache maintainers issued an advisory on Wednesday recommending users examine their systems to make sure they're not at risk.

"When using the RewriteRule or ProxyPassMatch directives to configure a reverse proxy using a pattern match, it is possible to inadvertently expose internal servers to remote users who send carefully crafted requests," the advisory stated. "The server did not validate that the input to the pattern match was a valid path string, so a pattern could expand to an unintended target URL."

The following article is from Apica about performance testing.

"Apica, a company dedicated to testing, monitoring, analyzing and improving Web performance, has helped Gulf News implement Web Performance enhancements, significantly improving overall response time and maximum load capacity.

Gulf News’ website, gulfnews.com, provides a huge amount of information on Web 2.0 sources. Its audience is geographically distributed across all countries in the Gulf region and globally.

Publishing the amount of information Gulf News provides, as well as the differences in bandwidth, devices and local Internet distribution for its audience, makes it important to be in control of Web performance.

Apica’s partnership with Atex and the company’s expertise and previous experience on the Polopoly platform was a key criterion for being awarded this work. Apica’s experienced test staff has years of knowledge in turning Polopoly installations and a head start in finding and eliminating performance problems that are Polopoly specific, if present.

The following is an article about load testing from Compuware.

"Microsoft’s Windows Azure has beaten all competitors in a year’s worth of cloud speed tests, coming out ahead of Amazon EC2, Google App Engine, Rackspace and a dozen others.

The independent tests were conducted by application performance management vendor Compuware using its own testing tool CloudSleuth which debuted last year. Anyone can get results from the past 30 days for free by going to the CloudSleuth website, but this is the first time Compuware has released results for an entire 12-month period.

Compuware uses 30 testing nodes spread around the globe to gauge performance of the cloud services once every 15 minutes. The company performed 515,000 tests overall for a year’s worth of data covering August 2010 to July 2011, which Compuware released today. Each test requires the loading of a simulated retail shopping site consisting of two pages, one page containing 40 item descriptions and small JPEG images, and the second page containing a single, larger image of 1.75MB.

The following is an article on performance testing written by Scott Price from LoadStorm

"Forgive me for stating the obvious, but web applications are a critical part of global business in 2011. I see no alternative other than more dependence by companies everywhere on web software and Internet infrastructure. In my opinion, all business trend data predicts greater overall web usage, more complex application architectures, and tremendous spikes in extreme traffic volumes.

Critical Applications, Yet They Aren't Getting the Investment Needed

ComputerWorld last week made a definitive statement regarding the critical nature of web applications:

Those who are unprepared are vulnerable to service outages, customer dissatisfaction and trading losses - and often when it hurts the most. Successful businesses understand the need to assure service and application availability if they want to retain customers, deliver excellent service and take maximum advantage of the opportunity their market offers.
This is not a theoretical problem - just look at the recent challenges for the London 2012 Olympics andTicketmaster. Just when everyone wants to do business with you, you’re not available.

The following is an article on load testing early and often to prepare for the holiday season.

"Internet shoppers are increasingly intolerant of slow performance and delay. Even very slight performance degradation can cause a significant percentage of them to abandon your site for the competition.

In recognition of this fact, some Internet retailers are already beginning to load test their sites in preparation for the holiday season. If this seems early to you, consider the following points:

Web applications are built using many more moving parts than in the past. These include, but are not limited to, Web servers, application servers, database servers, storage devices, mainframes, load balancers, firewalls, mobile components and carriers, media servers, ad servers, content delivery networks, analytics servers, and third party cloud services. All these moving parts add up to many potential bottlenecks.

The following is an article from Jim Holmes about performance testing.

"In this final post of my performance testing series I’ll help you figure out where to start, then pass on a few resources I’ve found extremely helpful in my own efforts.
What do I Monitor?
Figuring out which metrics, measurements, and counters to monitor can be extremely daunting—there are hundreds of individual counters in Performance Monitor alone! In most cases you don’t need anywhere near the entire set of metrics. A few counters will give us all the information you generally need for starting your performance testing work.
Most performance testing gurus will tell you just a few items will get you started in good shape:
Processor utilization percentage
ASP.NET requests per second
SQL Server batch requests per second
Memory usage (total usage on the server, caching usage)
Disk IO usage
Network card IO
If you’re doing load testing you’ll likely be interested in errors per second and queued requests. Often times soak or endurance testing will look to counters associated with memory leaks and garbage collection too—these help you understand how your application holds up over a long period of stress. However, those are different scenarios. The few counters mentioned above will get you started in good shape.
Where Can I Learn More?

The following article from neotys is about load testing.

"Neotys, a leader in easy-to-use, cost effective load testing tools for web applications, today announced the Celerity Innovation Center is using NeoLoad to performance test Adobe Flex web applications before they go "live" with customers. NeoLoad has cut load and performance testing time by 50%.

The Celerity Innovation Center develops web and mobile applications that streamline customer interactions, improve business processes and deepen user interactions. It is a rapidly growing company that has more than tripled in size during the past year. It attributes its success to its innovative spirit and staying active in meeting customers' needs.

Celerity has chosen Adobe Flex as its primary web development platform. Adobe Flex allows customers to have interactive, dynamic, and platform-independent applications with the flexibility of desktop applications in a Web environment. Consistent with best practices, the Celerity Innovation Center performs load tests for all of its applications. These tests identify possible bottlenecks enabling the Center to maximize performance before the go-live date.

A good article from Compuware about performance testing.

"Compuware Corporation CPWR +4.60% , the technology performance company, today said that its dynaTrace software division has announced that users of dynaTrace 4, its fourth-generation Application Performance Management (APM) platform, are enjoying unparalleled business value, shortened time-to-value and lower total cost of ownership for business and technology customers alike. dynaTrace 4 sets a new standard for APM, unifying it with User Experience Management (UEM) and Business Transaction Management (BTM) for the first time with the latest PurePath Technology(R). And, as characteristic of all dynaTrace releases, it continues to increase efficiency across the software performance lifecycle -- from production, to test, to development.

As applications become more business critical, managing performance from the user's perspective is a growing requirement for any modern APM system. By tightly integrating User Experience Management (UEM) with its transaction-pure APM system, dynaTrace 4 allows business owners to understand performance from the user's point of view for all page actions, whether these actions call content and resources in the data center or in the cloud. All user click-paths are captured as visits and aggregated for behavior analysis and accurate complaint resolution.

The following is an article from SOASTA on load testing.

"This is a guest post written and contributed by Fred Beringer, VP Business Development EMEA at SOASTA. SOASTA provides load and performance testing products as well as solutions available as on-demand cloud services.

Common wisdom used to hold that you can’t load test live applications, and any testing during development wouldn’t accurately reflect real world conditions. So, it’s not surprising that more than 75% of companies today don’t adequately test and validate the scalability of their apps. Everyone knows that load testing is the best way to ensure production systems can handle live traffic, and to identify bottlenecks before they cause catastrophic failure, but the costs and risks often outweighted the benefits… until now.

In partnership with Joyent, Soasta is offering the Soasta CloudTest Lite suite to all Joyent customers for free. Now you can integrate load testing as part of the design process, from development through launch, and load test live apps in production to spot things that will break under heavy load long before your customers get to that point.

Let’s take a look at the typical rationales for not load testing. Believe me, we hear these all the time.

The following article is about performance testing from uTest.

"uTest, the world's largest software testing marketplace, today announced that its CEO Doron Reuveni will present the "Top Ten Disruptive Technologies You Must Understand" at STARWEST 2011 in Anaheim, CA on October 5th at 1:45pm.
In this session, Reuveni addresses how crucial it is for technology executives and their organizations to be prepared to meet the challenges emerging technologies present to the world of app development and testing. The ways in which web and mobile apps are designed, developed, and delivered are changing dramatically, and therefore the ways these apps are being tested are being taxed and stretched to the breaking point.
Using real-world examples, Reuveni identifies the top ten disruptive technologies that have transformed the software industry and outlines what they mean for the testing community now and in the future.

The following is an article about load testing from Adrian Bridgwater.

"Those of us with a ticket to ride (to the cloud) gathered in a central London location earlier this week to hear Rackspace talk about its new Critical Sites service.

It's always nice to press the flesh with the real CEOs behind the IT industry -- and I got a quick chance to meet Rackspace president Lanham Napier at this week's event.

Napier is an affable Texan powerhouse of cloud-speak and enthusiasm. He is, as they say, a maverick -- and has been ranked as a captain of industry by Forbes, CNN and probably Ben & Jerry's ice cream for all I know.

So Napier and his board were in town to launch Critical Sites for (as Rackspace puts in) "extreme" mission-critical cloud deployments.

"The Critical Sites offering drills into the application layer to deliver mission-critical support for clients' most important websites and applications. Critical Sites customers receive access to a suite of performance management tools built to gain real-time visibility of the end user experience," said the company, in a press statement.

But what does 'drilling into the cloud application layer' really mean?

The following is a good article on load testing by Colin Mason.

"n this day and age, the web tends to be the number-one way businesses interact with their customers and prospects. Web performance—or the speed and reliability of your website, mobile site, and web applications—can have a huge impact on your business. According to the Aberdeen Group, a single-second delay in website response time translates to an 11 percent reduction in the number of pages customers and prospects view on your site, a 16 percent drop in customer satisfaction, and a 7 percent decline in conversions.

As a software tester or quality assurance professional, your job is to ensure superior website, mobile site, and web application performance, particularly during peak traffic periods when a business often has the most to gain (or lose). If the site is slow, you're going to lose customers to competition. If customers can't get through their transactions, you're not going to make money.
Years ago, load tests were designed to validate that your database, server, and internal network were ready to handle peak traffic loads (in the vicinity of one hundred users!). As websites, mobile sites and web applications have grown significantly more complex over the past decade, they now require a whole new set of techniques and practices for load testing.

The following is an article on load testing from Sergei Sokolor.

"Any load testing project should start with the development of a model for user workload that an application receives. This should take into consideration various performance aspects of the application and the infrastructure that a given workload will impact. A workload profile is a key component of such a model. Depending on the type and goals of a load test, one or more profiles may be appropriate. Choosing the workload profiles representative of anticipated real load over time (whether it is an everyday usage scenario or a high peak) results in more accurate answers to the “main questions of load testing” such as, “Will my site support N users performing a search at the same time?” and “What is the highest number of users that my site will support – while remaining within specified quality and performance guidelines?”

Workload modeling identifies one or more workload profiles to be simulated against the tested application. The workload model then attempts to approximate real life usage scenario and includes different user types and characteristics.

To determine the workload for your application, consider the following questions:

What is the set of possible actions that a user can perform?

The following is an article about load testing and performance testing.

"Organizations have finally realized that building brand loyalty online contributes significantly to the overall brand value of the organization. In order to achieve this brand loyalty in the online space, organizations need to focus on two key elements - user experience and application availability.

Organizations can improve their online end user experience by conducting usability testing and by taking feedback from users to uncover potential usability issues. Usability testing helps identify deviations from usability standards and provides improved design directions as part of its iterative design process.

Uninterrupted application availability can be achieved by focusing on the performance aspects of the business application. To do so, the prime focus needs to be on performance throughout the application life cycle stages, right from requirements gathering, understanding the business forecasts, accounting for seasonal and peak workloads, capacity planning for production and ensuring right disaster recovery strategies like multiple back-ups across geographies, etc. All these need to be further coupled with the right performance validation approach.

The following is an article on load testing by Compuware Corporation.

"Compuware Corporation (CPWR), the technology performance company, today announced that Enterprise Management Associates (EMA) cites that Compuware Gomez's 360° Web Load Testing Solution offers unique capabilities that are unmatched by competitors. EMA a leading analyst firm goes on to say that these capabilities strengthen Compuware's leadership in the application performance management (APM) market.

In the EMA Impact Brief report titled: "Compuware Gomez's 360° Web Load Testing Solution Unites Development and Operations with Unique Efficiencies," EMA Vice President, Dennis Drogseth wrote: "Through a series of judicious acquisitions, well-focused internal development, and a consistent and clear vision, Compuware has evolved its Gomez APM solution to address mainstream requirements across application, Internet and cloud ecosystems which few other vendor dare address, and virtually none can fully equal."

The following article about load testing is from Patrick Lightbody at Neustar.

"The good news for e-commerce retailers: Industry sources are predicting a successful 2011 holiday season. Though the economy is still fragile, eMarketer predicts that sales will match or surpass 2010 levels, with an estimated growth of 12%. Strong first-half online sales have provided nice momentum, with price-conscious consumers using the Web to compare and find the best deals.

Now the bad news: Every so often you hear about a retail site crashing — a victim of its own success — unable to handle higher traffic generated by an exclusive deal with a hot clothing line or highly anticipated product. While these tales are hardly exclusive to the holiday season, the increased traffic during the holidays means it's unquestionably the worst time for a storefront outage. In many cases, disaster isn't inevitable. There's a way to prepare your website and be ready for marketing driven events, or more pressingly, with Black Friday, Cyber Monday and all the days of Christmas.

Yes Virginia, it's that time of year for load tests.

Find Bottlenecks and Overall Site Capacity

The following is an article about performance testing.

"A rumor has swept around the world this week through Twitter and Facebook that Jason Buksh, performance consultant, is going to be an ongoing guest blogger for LoadStorm. That rumor has apparently been substantiated! You heard it here first. We look forward to many useful insights from Jason.

So, please welcome our newest performance test expert blog contributor here at LoadStorm.com.

As his first contribution (other than his insightful interview), he sent me this funny cartoon about stress testing."

http://loadstorm.com/blog

The following is an article by Tammy Wolf about load testing.

"Every year on Thanksgiving Day, Americans loosen their belts to make way for the wealth of turkey, stuffing and gravy gracing their dining tables. And the following day, Black Friday (News - Alert), they instead loosen their wallets (and bank accounts) to prepare for the abundance of sales and deals greeting them online and in stores.

This year will be no different when the holiday rush kicks off on Black Friday, Nov. 25. In fact, last year, U.S. e-commerce sales totaled a whopping $142.5 billion on Black Friday alone.

While Americans are just beginning to prepare for their pending shopping frenzy, e-commerce sites must take cautionary steps to accommodate the lion’s share of online sales that take place during the holiday shopping season.

Luckily, load testing and performance-monitoring provider Apica has the following top 10 recommendations for readying your e-commerce site for what’s sure to be a never-ending rush of holiday shoppers this season.

1. Put vanity aside: In order to minimize response times, Apica recommends limiting the number of high-resolution images and videos on your site. However, if you find yourself too attached to let them go, now is the time to invest in systems that can manage short response times as well as bulky content.

The following article is about load testing and performance testing.

"What is Load testing? Is load testing and performance testing same?
These are questions may arise for some who are new to testing , i have described below about Load testing.

What ever may be the domain and what ever may be the project but the customers expect the quality and at the same time the speediness and response time on navigation's , clicks , loading of a page or images etc.

After release of a product many people will be accessing it at a time. Hence the capacity of a product is also a important constraint.
So, to determine the capacity of the application in terms of number of users use the application at the same time.

Load testing:
Load testing belongs to a type of system testing. It is a type of system testing which involves in series of sequential load is applied on an application to verify and determine the bearing capacity of an application.

The load testing is again divided in to types as follows:

Initial Load:
Initial load is the load at which the load testing can be initiated on an application.
This involves in just invoking browser and opening the application.
Constant incremental Load:
Constant incremental load is a process of adding load to the previous load consistently every time load testing is performed.