Measuring and tuning the OS/390 Http Server Performance

Fabio Massimo Ottaviani
May 2001

For many years OS/390 have been the repository for enterprise mission critical applications and data while Unix played a fundamental role in the deployment of Web applications getting general acceptance as the favourite http servers Operative System.

This kind of “perfect” separation does not exist anymore. You have to make your choices in a brand new scenario in which :
• Intranet and Internet applications are becoming the most critical assets of every enterprise;
• Unix servers are “mainframe” systems provided with huge CPU power, memory, I/O and network bandwidth, and sophisticated software able to manage multiple complex workloads;
• S/390 is a real Unix system, TCP/IP based, able to support any kind of Web, e-Commerce and e-Business application.

Both of these Operative Systems (Windows 2000 can be included if you like) could effectively manage a web based enterprise. You can choose one or the other as your favourite “e-platform” depending on your company needs in terms of: security, availability, scalability, performance, costs, etc.

Once you have choosen a solution, you have to manage all the environment in order to achieve the service level objectives you agreed with your users. To do that you need reliable, complete and easy to use metrics.

In this paper I’ll discuss the major performance issues related to the OS/390 http server implementation trying to investigate:
• parameters available to tune Unix System Services and OS/390 Http Server from outside;
• metrics and parameters available to tune Unix System Services;
• metrics and parameters available to tune the OS/390 Http Server.