Web Performance Advisor

 

A part of the IBM HTTP Server for i5/OS, the Web Performance Advisor provides a way to view, evaluate, and modify the performance attributes for your Web environment.

A Web environment is a grouping of related Web and application servers that form a Web solution. A Web environment is typically made up of a single WebSphere Application Server instance or profile and all the application servers contained within, its corresponding IBM HTTP Server (powered by Apache), and any system attributes that could have a direct effect on the performance of the Web environment.

Information for this topic supports the latest PTF levels for HTTP Server for i5/OS . IBM recommends that you install the latest PTFs to upgrade to the latest level of the HTTP Server for i5/OS. Some of the topics documented here are not available prior to this update. See IBM Service for more information.

The Web Performance Advisor is made up of multiple components to help you tune the performance of your system and Web environment. These components include an advisor and an export function. These can be launched from the Web Performance Advisor introduction page. On this introduction page, the user is provided a quick, easy-to-read, high-level view of their system and Web environment performance.

The Advisor function allows you to manage system attributes and to manage Web environment attributes. From the manage system and manage Web environment panels, you can view, evaluate, and change each performance attribute. While evaluating each performance attribute, click the attribute's Advise link to learn about the attribute and find the recommended setting.

The export function allows you to save existing performance settings in a performance profile. This profile can be evaluated, compared, or sent to a performance expert for analysis and modification.

When the Web Performance Advisor tool is used to examine a Web related server, a flight recorder performance profile is created to save what all performance attributes are set to prior to any changes being made. Whenever changes are made through the Web Performance Advisor, all the performance attributes are saved (including the new changes) to another flight recorder performance profile file. This is necessary so that you can keep track of all changes made to a Web environment. All flight recorder performance profile files are located in the '/QIBM/UserData/HTTPA/admin/WPA' directory. The Web Performance Advisor tool does not clean up these files; they remain until someone deletes them manually. Because the attributes affecting performance in a Web environment are located in many places, the Web Performance Advisor combines all of the performance attributes into a performance profile. The profile contains:

 

Details

The Web Performance Advisor gathers ratings and recommendations for each of the performance attributes being tuned. From these ratings, icons are displayed to convey whether the attribute is tuned well (green), may need some additional tuning (yellow), or needs immediate attention (red). The ratings that are displayed may vary based on the risk level (conservative or aggressive) you have configured in the General Settings. Conservative means that you do not want to be alerted to those performance attributes that are on the fringe. By using the conservative approach, fewer attributes are changed and drastic performance updates are not made. Of course, performance may not be tuned as well, but there is much less risk of degrading your machine as a whole. Using the aggressive approach, any attribute that is on the fringe is flagged as needing to be changed. In addition, attributes that would be flagged as good in a conservative mode, might actually be flagged as needing improvement. By doing this, more drastic performance updates are made which may dramatically improve performance. On the downside, the possibility exists that unexpected, unwanted consequences may result from these drastic performance changes.

 

Prerequisites and assumptions

Support for the Web Performance Advisor was added in the PTF Group SF99114 Level 6. This level or higher is required to use this function. The Web Administration for i5/OS interface supports these Web browsers: Microsoft Internet Explorer 6.X and Mozilla FireFox 1.5.X. The Web Performance Advisor feature supports a wide variety of WebSphere based products. These include WebSphere Application Server, WebSphere Portal Server, and IBM Workplace. The other product that is supported is the IBM HTTP Server (powered by Apache) when the HTTP server is configured to be used by one of the previously listed products. Each of the following WebSphere Application Server products must be at the Fix level specified before Web Performance Advisor can work. When WebSphere Application Server fixes are installed, the activation instructions must be followed completely, and the ADMIN server must be stopped and restarted. The following versions are supported:

 

Start the Web Performance Advisor

The Web Performance Advisor can be started from the Web Administration for i5/OS interface:

  1. In iSeries Navigator, expand your_system_i –> Network –> Servers, and select TCP/IP.

  2. Right-click HTTP Administration, and select Start.

  3. Start a Web browser.

  4. Type http://[your_system_i]:2001 in the URL field to start the i5/OS Tasks Web page, where [your_system_i] is the name of your IBM i5/OS system. Example: http://mysystemi.acme.com:2001

  5. Click IBM Web Administration for i5/OS.

  6. From the IBM Web Administration for i5/OS interface, select the server you want to examine.

  7. In the navigation pane, expand Web Performance, and select Web Performance Advisor.

    If Web Performance Advisor is not displayed in the navigation pane, either the correct level of PTF Group SF99114 has not been properly installed, or the selected server is not supported by the Web Performance Advisor.

The Web Performance Advisor introduction page displays. From this page, you can select to manage your system or your Web attributes, change your general settings, or export your current performance settings.

More performance tuning tools

The Web Performance Advisor is only one tool available for you to tune your performance settings. The Web Performance Advisor, the Workload Estimator, and the documented minimums are all tools available to help you achieve improved performance. These resources can be used together to find the settings that are best for you.

Documented minimums: This is the smallest possible system you should run on. These systems may be appropriate for development or internal systems with a small number of users where longer response times are acceptable. Good performance is not expected on these systems.

Workload Estimator: This tool accounts for the specific characteristics of your workload to recommend an appropriate system. It should be used to determine the size and type of system that should be used based on the type of workloads you plan on running. It cannot recommend a system that is smaller than the documented minimum recommendations, but it may recommend a larger system.

Web Performance Advisor: This tool is recommended if you are trying to get good performance out of your applications and environment. It may recommend configurations that are somewhat larger than the documented minimums. The recommendations could, however, be smaller than the Workload Estimator recommendations, because the Web Performance Advisor does not account for the specific workload your system faces during the runtime of your applications or other things that may be running on your system.

 

Parent topic:

Web tasks