HP essential knowledge series: an introduction to load testing for web applications. White paper

Transcription

1 HP essential knowledge series: an introduction to load testing for web applications White paper

2 Table of contents Introduction Grow your business with e-commerce Improve the customer experience Application load testing prior to going live The challenges of automated load testing tools The process of automated load testing Step 1: Perform system analysis Step 2: Create virtual user scripts Step 3: Define user behavior Step 4: Create a load test scenario Step 5: Create network impact tests Step 6: Run the load test scenario and monitor the performance Step 7: Analyze results HP LoadRunner Step 1: Perform system analysis Step 2: Create virtual user scripts Step 3: Define user behavior Step 4: Create a load test scenario Step 5: Create network impact tests Step 6: Run the load test scenario and monitor the performance Step 7: Analyze results Summary

3 All companies face the same challenges in conducting business online: high customer volumes, slow response times for web requests and the need for reliable service. Introduction If your company uses the web to sell products or services, in order to be successful you need to provide customers with a positive online experience. Unfortunately, many companies lose customers because their sites can t handle surges in web traffic. For example, the successful promotion of a product or service that stimulates web traffic can be a boon for businesses as long as they are able to respond to online customer demand. If not, waiting customers become impatient and simply click to a competitor s website, which compromises a company s revenue growth. All companies face the same challenges in conducting business online: high customer volumes, slow response times for web requests and the need for reliable service. In this white paper, we ll show you how maintaining web-application performance is key to overcoming these e-business challenges and generating revenue. We ll then discuss the importance of having a more efficient web application to satisfy customers and why load testing is critical to successfully launching and managing websites. Next, we ll examine various types of load testing and provide a detailed discussion on the load testing process and the attributes of a reliable testing tool. Finally, we ll provide an overview of HP LoadRunner software, our industry-standard performance validation software. Grow your business with e-commerce E-commerce is now a standard operating procedure for many businesses. Today, it is estimated that more than 1.1 million people use the Internet and there is no sign of a slowdown. E-commerce has become a popular medium for buying and selling products and services for two reasons: It allows businesses to share information and resources worldwide, and it offers an efficient channel for advertising, marketing and sales. By using the Internet, businesses are able to improve their sales and marketing scope, provide more services to customers, and more efficiently conduct business internally and externally. With the number of Internet users rising and the competition among vendors increasing, businesses realize the importance, as well as the challenges and rewards, of providing customers with a positive experience. After all, customers satisfied with their online experience are likely to engage in repeat business and provide a steady stream of revenue. As a result, providing customers with a positive online experience ranks among the top priorities for companies e-commerce. 3

4 Figure 1. The schematic of a complex web infrastructure Internet Clients Routers Switches Web servers Internet firewall Load balancers Application servers Database servers and other database sources Improve the customer experience Despite the potential rewards of conducting business online, doing so can be very complex. According to a report by the IBM High-Volume Web Sites (HVWS) team, commercial websites can be classified into four categories based on the types of business transactions they perform: publishing/subscribers, online shopping, customer self-service and trade/auction sites. By understanding these categories, you can better predict your customer volume and understand how they prefer to use your website. Below is an overview of the different commercial website categories: Publishing/subscriber sites provide customers with media information, such as magazine and newspaper publications. Although the total number of customers is generally low on these sites, the number of individual transactions performed on a per-customer basis is relatively high. This gives this category the largest number of page views of all site categories. Online shopping sites allow customers to browse and shop for anything found in a traditional brick-and-mortar store. Traffic is heavy, with daily volumes ranging between one and three million hits per day. Customer self-service sites include banking and travel-reservation sites. Security considerations (e.g., privacy, authentication, site regulation, etc.) are high. Trade/auction sites allow users to buy and sell commodities. This type of site is volatile, with very high transaction rates that can be extremely time-sensitive. Whatever the transaction type, you must enable your customers to conduct business in a timely manner. For this reason, you need a scalable architecture. A well-structured web environment, however, consists of an extremely complex multi-tier system. Scaling this infrastructure from end-to-end means managing the performance and capacities of individual components within each tier. Figure 1 above illustrates the complexity of these components. This complexity triggers many questions about the integrity and performance capabilities of a website. For instance, will the response time experienced by the user be less than two seconds? Can the website sustain a given number of users? Can all the interoperable pieces of the system work together? Is communication between the application server and the database server fast enough? Is there sufficient hardware on each tier to handle high traffic volumes? Will the clients have quality experiences over wide area networks (WANs)? To reduce these performance issues, you must be able to predict how web applications behave in a production environment before your website goes live. 4

5 Figure 2. A single console controlling several thousand Vusers replaces manual testers. Internet Virtual users Web server Application server Database Manual testers Control console Application load testing prior to going live To accommodate the growth of your sites, you may want to enhance software or add hardware to each component of the system. However, random attempts to improve performance are not ideal and can lead you to overbuy hardware without knowing whether or not it will succeed. Load testing the complete assembly of your system prior to going live enables better performance. Application load testing is the measure of your web application s ability to conduct multiple transactions simultaneously while maintaining adequate response times. Because it is comprehensive, load testing is the only way to accurately test the end-to-end performance of a website prior to going live. Application load testing enables you to isolate bottlenecks in any component of the infrastructure. Two common methods for implementing this process are manual and automated testing. Unfortunately, manual testing has several inherent challenges, such as determining how to: Emulate the behavior and load of hundreds to thousands of users who interact with the application Coordinate user operations Measure response times Repeat tests in a consistent way Compare results Manual testing is also not the most practical option because you must identify performance problems, tune the system and retest to verify that tuning has had a positive impact. With automated load testing tools, you can automatically rerun the test and measure results. In this way, automated testing tools provide a more cost-effective and efficient solution than their manual counterparts. They also reduce the risk of human error during testing. Today, automated load testing is the preferred choice for load testing a web application. The testing tools typically use three major components to execute a test. These include: A control console that organizes, drives and manages the load Virtual users (Vusers) processes used to imitate a real user performing a business process on a client application Load servers (used to run the Vusers) Using these components, automated load testing tools can: Replace manual testers with automated Vusers Simultaneously run many Vusers on a single loadgenerating machine Automatically measure transaction response times Easily repeat load scenarios to validate any design changes you make to optimize performance This advanced functionality allows you to save time and costly resources. The Newport Group recently demonstrated the value of automated testing tools in a report that revealed that more than half of web-based businesses did not meet their anticipated web-based business scalability objectives. Of these, most did not use any type of automated load testing tool. In contrast, nearly all of the businesses that met their scalability expectations had used an automated load testing tool. 5

6 Figure 3. Automated load testing enables businesses to meet scalability expectations. Did your application scale as expected? From 48 percent did you use an automated load testing tool? From 52 percent did you use an automated load testing tool? Yes 48% No 52% Yes 70% No 30% No 60% Yes 40% The challenges of automated load testing tools The primary challenges of load testing tools include the ability to be accurate and scalable and to isolate performance problems. To isolate performance problems, load testing tools monitor key system-level components and identify bottlenecks during the run of a load test. Accuracy is defined by how closely an automated tool can emulate real-user behavior. Scalability relates to the product s ability to generate more load using fewer resources. In order to provide reliable end-to-end testing, automated load testing tools must address all aspects of accuracy and scalability and be able to pinpoint problems. Listed below are some key characteristics of accuracy and scalability. Figure 4. Accuracy and scalability are key attributes in load testing. Accuracy Record ability against a real client application. Capture protocol-level communication between the client application and the rest of the system. Provide flexibility and the ability to define configurations for user behavior (e.g., think times, connection speeds, cache settings, iterations, etc.). Verify that the requested content returns to the browser to facilitate a successful transaction. Show detailed performance results that can be easily understood and analyzed to quickly identify the source of the problems. Measure end-to-end response times. Use real-life data. Synchronize Vusers to generate peak loads. Monitor different tiers of the system with less intrusion. Scalability Generate more Vusers that can be run on a single machine before exceeding its capacity. Generate more hits per second against a web server. Manage thousands of Vusers. Increase the number of Vusers in a controlled manner. Simulate the effect of scaling out to remote locations over WANs. 6

7 The process of automated load testing With disciplined load testing, you can optimize resources; better predict hardware, software and network requirements; and set performance expectations to meet customer service-level agreements (SLAs). You must be able to repeat the testing process in order to verify what changes may have taken place. Listed below is a step-by-step overview of the automated load testing process. Step 1: Perform system analysis This step is critical to interpreting your testing needs and is used to determine whether the system can scale and perform to your expectations. When testing, you basically translate your users requirements into load testing objectives. A thorough evaluation of the requirements and needs of a system before beginning load testing can provide more realistic test conditions. First, you must identify your key performance goals and objectives before testing. These may include identifying which processes and/or transactions to test, which system components to use in the test, and the number of concurrent connections and/or hits per second to expect against the website as well as clarifying which processes are to be tested. By referring to the four models of websites (see page 4), you can easily classify your site s process and/or transaction type, which can allow users to complete their transactions faster. For example, a business-toconsumer model can implement an online shopping process in which a customer browses through an online bookstore catalog, selects an item and makes a purchase. This process could be labeled buy book for the purposes of the test. By defining these objectives, you can provide a concise outline of the SLAs and mark the goals to be achieved with testing. Second, you need to define the input data used for testing. This data can be created dynamically. For example, auctioning bids may change every time a customer sends in for a new request. Random browsing also may be used to obtain the data. Examples include any non-transactional process, such as browsing through a brochure or viewing online news. By anticipating your customers actions and needs, you can avoid potential problems with inaccurate load test results. Third, you must determine the appropriate strategy for testing applications. You can select from three strategy models: load testing, stress testing and capacity testing. You may use load testing to test an application against a requested number of users. Your goal is to determine whether your site can sustain this requested number of users with acceptable response times. Stress testing, on the other hand, is load testing over extended periods of time to validate an application s stability and reliability. The last strategy is capacity testing. You may use capacity testing to determine how many users can use your site simultaneously. For example, you would use capacity testing to benchmark how much customer traffic your sites can sustain before experiencing system failure. Fourth, you need to cultivate a solid understanding of your system s architecture, including: Defining the types of routers and network connectivity you re using in the network setup Determining whether you re using multiple servers Establishing whether you re using load balancers as part of the IP networks to manage the servers Determining which servers are configured into the system (web, application and database) 7

8 Finally, you must know which resources are available to run the Vusers by deciding whether you have sufficient numbers of load generators or test machines to run the appropriate number of Vusers. You must also determine whether the testing tool has multi-threading capabilities and can increase the number of Vusers being run. Ultimately, your goal is to reduce your consumption of system resources while increasing the number of Vusers. Step 2: Create virtual user scripts You use a script recorder to capture all the business processes into test scripts, which are often referred to as Vuser scripts or Vusers. A Vuser emulates the real user by driving the real application as a client. You must identify and record all the various business processes from start to finish. This can help you determine the amount of time you need to measure the performance of a business process. Step 3: Define user behavior Run-time settings define the way the script runs in order to accurately emulate real users. Settings can configure think time, connection speed and error handling. Think times can vary depending on your customer s action and familiarity with web technology. For example, users less comfortable using the Internet may take more time to complete their transactions. As a result, you need to account for a user who takes a longer time between actions. Advanced users, however, have much more experience and can complete their transactions quickly, often bypassing steps. Your system s response time can vary also because it is dependent on connection speed, and all users connect to the web system at different speeds (e.g., modem, LAN/WAN). WAN emulation accurately simulates a variety of connections at varying network bandwidth and latencies (e.g., 56.6 Kbps, 1 Mbps, etc.). This can help you determine how the underlying network affects application response times. Because errors can arise throughout a scenario and impede testing, you also need to configure error handling. You can configure Vusers to handle these errors so you can run the tests uninterrupted. Network communications errors can also profoundly influence application response times. You can also configure WAN emulation to introduce underlying network errors to understand their impact and measure the application s tolerance for them. Step 4: Create a load test scenario The load test scenario contains information about the groups of Vusers that can run the scripts and the load machines on which the groups are running. To run a successful scenario, you must first categorize your customers into groups based on their transactions. Second, you need to define and distribute the total number of Vusers. You can assign a varying number of Vusers to individual business processes to emulate user groups performing multiple transactions. Third, you must determine which load-generating machines the Vusers can run on. You can add loadgenerator machines to the client side of the system architecture to run additional Vusers. Finally, you need to specify how the scenario runs. You can either run the Vuser groups in staggered or parallel formation. Staggering the Vusers allows you to examine a gradual increase of the user load to a peak. Step 5: Create network impact tests The network test uses information about where the groups of Vusers can be located relative to the server. During the test, only the network characteristics such as bandwidth availability, contention, latency, errors and jitter can change; the number of Vusers in this test remains constant. By staggering the decreases in network bandwidth or increases in latency, errors and jitter, you can understand their relative influence on application behavior. This data can be used to set network requirements for the application when it is deployed. You can conduct this kind of testing directly over the network to remote locations, but for testing purposes it is generally more practical to emulate the network where you can easily establish a variety of conditions using WAN emulation. This can allow you to predict the performance for remote users. Step 6: Run the load test scenario and monitor the performance You can view the application s performance at any time during the test using real-time monitoring. Every component of the system requires monitoring: the clients, the network, the web server, the application server, the database and all server hardware. You can detect performance bottlenecks early during testing using real-time monitoring. You then have the ability to view the performance of every single tier, server and component of the system during testing. As a result, you can instantly identify performance bottlenecks during load testing. This can allow you to accelerate the test process and achieve a more stable application. 8

9 Figure 5. This is a generic graph showing performance under load so that you can identify bottlenecks. For example, if you want to know about the user threshold at two seconds, the results here show a threshold of 7,500 concurrent users. Figure 6. This graph is a generic display of the number of transactions that passed or failed. In this example, if the goal is to obtain a 90 percent passing rate for the number of transactions, then transaction 2 fails. Approximately 33 out of 100 transactions failed. Step 7: Analyze results This is the most important step in collecting and processing the data to help you resolve performance bottlenecks. The analysis can produce a series of graphs and reports that help summarize and present the end-to-end test results. For example, Figure 5 uses generic data to display a standard performance under load graph that shows the total number of Vusers against the response time. You can use this to determine the number of customers that can use your site simultaneously until response times become unacceptable. Figure 6 depicts a transaction overview showing the total number of transactions that passed in a scenario. Using the analysis of these types of graphs, you can isolate bottlenecks and determine which changes you need to make to improve system performance. After these changes are made, the tester must rerun the load test scenarios to verify the adjustments. HP LoadRunner HP LoadRunner is load testing software that predicts system behavior and performance. It exercises an entire enterprise infrastructure by imitating the behavior of any number of users (from one to thousands) to identify and isolate problems. HP LoadRunner can support multiple environments and test an entire enterprise infrastructure and applications including e-business, enterprise resource planning (ERP), customer relationship management (CRM) and custom client/server applications allowing you to improve your application s performance. By imitating the behavior of a real user, HP LoadRunner can test applications communicating with a wide range of protocols, such as HTTP(s), COM, CORBA and Oracle applications. HP LoadRunner also features a seamless integration with HP Business Availability Center software. 9

10 Figure 7. The VuGen allows you to capture business processes to create Vusers. As a result, you can use the same tests created during testing to monitor the application once it goes live. HP LoadRunner enhances every step of the load testing process to offer you good return on your investment. We can now show you how HP LoadRunner offers support for each segment of the load testing process. Step 1: Perform system analysis HP LoadRunner advocates the same system analysis we mentioned previously in this paper. It is important that you identify all testing conditions when you emulate a test environment, including the system architecture components, the processes being tested and the total number of Vusers you intend to test. A good system analysis can enable you to convert your goals and requirements into a successful, automated test script. Step 2: Create virtual user scripts You begin by recording the business processes to create a test script. You can accomplish this with HP LoadRunner Virtual User Generator (VuGen). VuGen is a component that runs on a client desktop to capture the communication between the real client application and the server. VuGen can emulate the exact behavior of a real browser by sending various e-business protocol requests to the server. VuGen also can record against Netscape or Internet Explorer browsers or any user-defined client that provides the ability to specify a proxy address. After the recording process, it can generate a test script. You can then add logic and intelligence to the script to make it more realistic and imitate a real customer making transactions on the website. HP LoadRunner executes this stage using the transactions, as well as its verification and parameterization features. Transactions: Transactions represent a series of operations that must be measured under load conditions. A transaction can be a single URL request by a customer or a complete business process leading through several screens, such as your customer purchasing a book online. Verification: VuGen allows you to insert verification checkpoints using ContentCheck, which enables successful transactions by verifying that the application is functional by analyzing the returned HTML web page to facilitate a successful transaction. If the verification fails, HP LoadRunner can log the error and highlight the reasons for the failure (e.g., broken link, missing images, erroneous text, etc.). Parameterization: To accurately emulate real-user behavior, HP LoadRunner Vusers use varying sets of data during load testing and replace constant values in the script with variables or parameters. The Vuser can substitute the parameters with values from a data source, such as flat files, random numbers, date/time, etc. This allows many different users to perform a common business process, such as searching for or ordering a book. 10

11 Figure 8. The run-time settings are used to emulate the real user as closely as possible. In this example, think time is randomly generated to simulate the speed at which the user interacts with the system. Step 3: Define user behavior HP LoadRunner provides comprehensive run-time settings to configure scripts that emulate the behavior of real users. Listed below are examples of run-time settings: Think time: Controls the speed at which the Vuser interacts with the system by including pauses of think times during test execution. By varying think times for users, HP LoadRunner can emulate the behaviors of different users from novice to expert. Dial-up speed: Emulates a user connected to the system using a modem and/or LAN/WAN connections. Modem speeds range from 14.4 Kbps to 56.6 Kbps. This is useful for controlling user behavior in order to accurately emulate response times for each request. Emulate cache: Emulates a user browsing with a specific cache size. Caching can be turned off based on server requirements. Browser emulation: Enables you to specify which browser the Vuser emulates. HP LoadRunner supports Netscape and Internet Explorer, as well as any custom browser. Number of connections: Allows the Vuser to control the number of connections to a server, like a real browser, to download web page content. IP spoofing: Tests the performance impact of IPdependent components by assigning Vusers their own IP addresses from the same physical machine. Iterations: Commands repetition of Vuser scripts and paces Vusers, instructing how long to wait between intervals. Iterative testing defines the amount of work a user does based on the number of times a process is performed using varying data. Error handling: Regulates how a Vuser handles errors during script execution. HP LoadRunner can enable the Continue on Error feature when the Vuser encounters an error during replay. Log files: Stores information about a Vuser s server communication. Standard logging maps all transactions, rendezvous and output messages. Extended logging also tracks warnings and other messages. 11

12 Figure 9. The HP LoadRunner controller is an interactive environment for organizing, driving and managing the load test scenario. Step 4: Create a load test scenario HP LoadRunner controller is used to create scenarios, providing you with complete visibility of the tests and the Vusers under a single point of control. The controller facilitates the process of creating a load test scenario by allowing you to: Assign scripts to individual groups Define the total number of Vusers needed to run the tests Define the host machines on which Vusers are running In addition, HP LoadRunner offers a scenario wizard, a scheduler and TurboLoad to enhance your experience during testing. The HP LoadRunner scenario wizard allows you to quickly compose multi-user load test scenarios. Using five easy-to-follow screens, the scenario wizard leads you through a process of selecting the workstations that can host the Vusers, as well as the test scripts to run. During this step-by-step process, you also create simulation groups of Vusers. The HP LoadRunner scheduler is used to ramp Vuser numbers up or down in order to position Vusers in both the ready state and the running state. For example, you may want to gradually increase the number of customers logging onto your site with a fixed batch size. This is referred to as the ready state. This method helps avoid unnecessary strain on the system. The central processing unit (CPU) consumption minimization feature improves scalability. HP LoadRunner can decrease CPU consumption for each Vuser, enabling more users to run on each load generator machine. In recent customer benchmarks, using ten Microsoft Windows -based load servers, HP LoadRunner generated more than three billion web hits per day against the web system (or 3,700 hits per second per machine). Moreover, the load generators were running at less than 40 percent CPU utilization. Step 5: Create network impact tests HP LoadRunner has the ability to handle WAN emulation, so you can use the same virtual-user scripts used in the previous steps for network impact tests. Network characteristics such as connection speed, latency and error rates are modified for groups of Vusers that are simultaneously emulated during a single test run. You can then accurately determine the impact of the network on response time on the different groups, as well as the sensitivities of the application to the network. You can record expected response time data and network requirement set for use later when the application goes live. The scheduler also manages scheduling and features an automated process that allows the user to run the script without being present. In real time, this would be similar to running a script during off-peak hours of Internet traffic 6 p.m. to 6 a.m. To schedule a test, you simply click the Run Scenario button and enter the desired starting time. 12

13 Figure 10. HP LoadRunner online monitors help identify and isolate performance bottlenecks in real time. Figure 11. Shown are the results of a website after testing the number of concurrent users its existing system can handle. Step 6: Run the load test scenario and monitor the performance Once the scenario is built, you are ready to run the test. The HP LoadRunner controller provides a suite of performance monitors that can monitor each component of a multi-tier system during the load test. By capturing performance data over the entire system, you can correlate this information with the end-user loads and response times to identify bottlenecks. HP LoadRunner provides performance monitors for the network and network devices, as well as the most common web servers, application servers and database servers. The performance monitoring is completely non-intrusive and performance impact is reduced. Additionally, all of these monitors are hardware and operating system (OS) independent, so they do not require that agents be installed on the remotely monitored servers. HP LoadRunner supports a number of environments to provide you with more accurate online monitoring, including: Runtime graphs: Vuser status, user-defined data points Transaction graphs: response time, transactions (pass/fail) Web-server resource graphs: hits per second, throughput, Apache, Microsoft Internet Information Server (IIS), Netscape System resource graphs: server resource, SNMP Tuxedo Web-application server graphs: BroadVision, ColdFusion, Microsoft Active Server Pages, SilverStream, WebLogic Database server resource graphs: SQL Server, Oracle 13

14 Figure 12. This activity graph displays the number of completed transactions (successful and unsuccessful) performed during each second of a load test. This graph helps you determine the actual transaction load on your system at any given moment. The results show that after six minutes an application is under a load of 200 transactions per second. Figure 13. This performance graph displays the number of transactions that passed, failed, aborted or ended with errors. For example, these results show the Submit Search business process passed all its transactions at a rate of approximately 96 percent. Step 7: Analyze results Analyzing results is the most important step in the load testing process. Up until now, you have been able to precisely record and play the actions of a real user with extreme precision, while conducting multiple transactions on the web. In addition, you have been able to accurately identify bottlenecks while running scripts using the performance-monitoring feature. Now you can take several steps to fix any problems that are identified. First, a network specialist (database administrator, consultant) can make the necessary adjustments to the system. Then you need to rerun the scripts to verify that the changes have taken place. Finally, you can measure the amount of improvement the system has undergone using a comparison of the results before and after the testing. The HP LoadRunner analysis component provides a single integration environment that collectively gathers all the data generated throughout the testing cycle. Because this tool is powerful and easy to use, you can create cross-scenario comparisons of the graphs to enrich the data analysis process. For example, Figure 11 shows the results of a website after testing the number of concurrent users that its existing system can handle. Based on these results, the company plans to improve its infrastructure to allow increased customer traffic. HP LoadRunner analysis provides advanced drill-down capabilities that enable you to identify bottlenecks in these scenarios. In addition, HP LoadRunner analysis uses a series of sophisticated graphs and reports that answer such questions as: What was the web server s CPU memory when the system was under a load of 5,000 simultaneous users? How many total transactions passed or failed after the completion of the load test? How many hits per second did the web server uphold? What were the average transactions times for each Vuser? Figures 13 and 14 are sample graphs that HP LoadRunner analysis provides you as it solves complex bottleneck issues. Running Vusers: displays running Vusers during each second of a scenario Rendezvous: indicates when and how Vusers were released at each point 14

15 Figure 14. This performance graph displays the minimum, average and maximum response times for all the transactions in the load test. This graph helps compare the individual transaction response times in order to pinpoint where most of the bottlenecks of a business process occur. For example, the results of this graph show that FAQ business process has an average transaction response time of seconds. This would be an acceptable statistic in comparison to the other processes. Figure 15. This web graph displays the number of hits made on the web server by Vusers during each second of the load test. This graph helps you evaluate the amount of load Vusers generate in terms of the number of hits. For instance, the results provided in this graph indicate an average of 2,200 hits per second against the web server. Transaction/sec (passed): displays the number of completed, successful transactions performed per second Transaction/sec (failed): displays the number of incomplete, failed transactions performed per second HP LoadRunner provides a variety of performance graphs, listed below: Percentile: analyzes percentage of transactions that were performed within a given time range Performance under load: indicates transaction times relative to the number of Vusers running at any given point during the scenario Transaction performance: displays the average time taken to perform transactions during each second of the scenario run Transaction performance summary: displays the minimum, maximum and average performance times for all the transactions in the scenario Transaction performance by Vuser: displays the time taken by an individual Vuser to perform transactions during the scenario Transaction distribution: displays the distribution of the time taken to perform a transaction HP LoadRunner offers two types of web graphs, listed below: Connections per second: shows the number of connections made to the web server by Vusers during each second of the scenario run Throughput: shows the amount of throughput on the server during each second of the scenario run HP LoadRunner analysis includes a Correlation of Results feature to enhance the user analysis process of the data. This allows you to custom design a graph beyond the basics using any two metrics. As a result, you can identify and troubleshoot performance problems more quickly. Summary E-commerce has quickly proven to be a viable way for both web-based businesses and brick-and-mortar companies to sell their products and services. With the number of Internet users growing exponentially, it is critical for you to be prepared and continually enhance your system to allow for increased customer traffic and transactions. You can do this by using load testing practices and software to help your website keep up with your customers demands. 15

16 Figure 16. This web graph displays the amount of throughput (in bytes) on the web server during the load test. This graph helps you evaluate the amount of load Vusers generate in terms of server throughput. For example, this graph reveals a total throughput of more than 7 million bytes per second. Figure 17. Using a compilation of results from other graphs, this graph correlates the relationship of the system behavior to the number of users. This enables you to view the CPU consumption based on the total number of users. By using automated load testing tools, you can also quickly and cost-effectively assess the performance of applications before they go live, as well as analyze their performance after they go live. As a result, you can confidently stay one step ahead of performance issues and focus your energy on increasing web traffic and revenue. HP LoadRunner software helps you predict the scalability, reliability and performance issues of an e-business application. It also helps you identify system bottlenecks and display results. HP LoadRunner imitates a variety of real customer transactions using a highly scalable number of users. This helps you understand an application s limitations while planning for growth and reducing business risk. HP LoadRunner also tests system behavior under real-time conditions and converts this data into easy-to-use yet detailed graphs and reports. With this information, you can more quickly and efficiently resolve problems, enabling a positive customer experience and providing your business with the opportunity to increase revenue. Download a ten-day trial of HP LoadRunner and see how load testing your applications in pre-production may save you time and money when you re ready to go live. To access the ten-day trial, go to and click on HP Performance Center. To learn more, Copyright 2007 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice. The only warranties for HP products and services are set forth in the express warranty statements accompanying such products and services. Nothing herein should be construed as constituting an additional warranty. HP shall not be liable for technical or editorial errors or omissions contained herein. Microsoft and Windows are U.S. registered trademarks of Microsoft Corporation. Oracle is a registered U.S. trademark of Oracle Corporation, Redwood City, California. 4AA1-3944ENW, August 2007