Operating Systems

Health Checking for z/VSE

5 Pages

As a continuously developed, steadily enhanced operating system, VSE offers many advantages, such as system stability, compatibility, and performance, in rapidly changing heterogeneous environments. However, the interrelations between many different system components and their huge number of functions and parameters involve some complexity, which is often difficult to understand, even from a systems programmer’s perspective. 

This situation has led to the idea of an automated tool to provide an overall preventive Health Check by collecting VSE status and performance data and displaying aggregated information in a user-friendly, comprehensive way. Retrieved information can also be analyzed by applying a given set of rules, making it possible to express recommendations about how to optimize relevant system parameters. (For a detailed analysis on this, see “Design and Implementation of an XML-Based Rule Component for Health Checking on the VSE Operating System,” a diploma thesis by Jürgen-Hendrik Kuhn, Berufsakademie Stuttgart, September 2004, IBM Lab Boeblingen, Germany.)

 Initial Prototype

From the first idea about a VSE Health Checker utility in Hans Joachim Ebert’s workshop, “Health Check for VSE/ESA” in 2002, it took one year to develop an initial prototype that was presented to customers at the Guide Share Europe (GSE) conference in Ulm, Germany, in October 2003. The prototype included these major functions: 

  • Automated retrieval of VSE system and performance data
  • Graphical data display
  • Portability of collected data by allowing storage of all collected information on disk in XML-format, facilitating data exchange via e-mail.

Only VSE base functionality is used for data retrieval, no optional products or third-party products. The tool never applies any changes to the VSE system, it just reads data. 

Figure 1 shows the Health Checker’s main window with a display of the CICS TS storage layout below the line. The VSE Health Checker’s Graphical User Interface (GUI) is divided in a tree view on the left side of the main window, showing all considered VSE system components in a hierarchical view. For each component, there’s a tabbed pane on the right side of the main window showing selected parameters and their actual values. Graphical charts help to visualize the information. 

Advantages  

The first prototype collected selected system data in an automated way, relieving the user from typing console commands, submitting jobs, invoking CICS transactions, and manual data evaluation. Here are some additional benefits of VSE Health Checker: 

  • Displayed information is aggregated from the output of multiple console commands or job listings. With priority settings, for example, data from console commands PRTY, D DYNC, and MAP for each static and dynamic partition can be collected and put together (see Figure 2).
  • Displayed values are calculated from different single retrieved values. (In
  • Figure 2, see size of the POWER partition above the line. This value is important, because if there are at least 2 to 3MB free space above the line, the POWER queue file can be kept in memory.)
  • Unimportant information (such as VTAM buffer usage) is removed. (In Figure 3, see the simple table from a large textual output of the DNET,BFRUSE command.)

Automated rule-based analysis is beneficial, as is the ability to detect possible problems before they show up (an example of the preventive service concept). System stability and performance can be optimized with recommended values of the various system parameters. Finally, working with the tool might help systems programmers hone their skills. 

5 Pages