Establishing Application Availability Goals

Applies To: Windows Server 2003, Windows Server 2003 with SP1

To set effective availability goals for your applications, you need to measure the availability of the World Wide Web Publishing service (WWW service), your Web sites, and the worker processes that service your applications. These availability measurements can be calculated as a percentage by dividing the uptime of the WWW service, Web site, or worker process by the time elapsed. In addition, a good user application availability experience depends upon successful handling of correctly formed requests, which are requests that are complete and error-free.

At times, users cannot access your applications because of these common request-handling problems:

• Correctly formed requests are sent, but they are not correctly served.

• Correctly formed requests are sent, but they are served only after a time interval that is unacceptable to the user.

To ensure that you set application availability goals that represent the needs of your users, you must first define how you will measure the successful serving of requests. Make sure that your goals address the following:

• Service availability, which includes the WWW service and individual Web sites.

• Application availability, which includes request processing reliability and the average time that is needed to process requests.

Figure 4.2 shows the process for establishing application availability goals.

Figure 4.2   Establishing Application Availability Goals