Understanding the Exception Monitor


For each system resource, you can specify an upper limit for utilization called a threshold.

The Exception Monitor continuously monitors the resource at specified intervals and generates a warning message if that threshold is exceeded. These messages are displayed both in the WARN view and on the z/OS console. By monitoring Exception Monitor messages, you can take steps to correct problems or potential problems before they severely impact performance.

Important

To address potential problems automatically, you might want to set up a BMC AMI Ops Automation Solution that is triggered by warning messages. For more information, see BMC AMI Ops Automation.

How the Exception Monitor knows what to monitor

The Exception Monitor tracks system resources according to the samplers that are specified in the currently active control statement member:

  • A sampler is a program that monitors a particular aspect of system performance. BMC AMI Ops Monitor for z/OS provides a diverse set of samplers from which to choose to monitor activities such as enqueue conflicts, various types of I/O activity, and CPU utilization.
  • A control statement member is a collection of one or more samplers.Each member contains the initial threshold settings for its constituent samplers, which you can either keep or alter. Only one control statement member can be active at a time. OpsM for z/OS ships two default control statement members, PWSCPM00 (which is modifiable) and PWSCPMXA (which is not).

Both PWSCPM00 and PWSCPMXA contain all of the available OpsM for z/OS samplers and therefore monitor every possible aspect of system performance. However, by using the Exception Monitor Member List, you can create your own control statement members to contain a subset of samplers, thus monitoring only specific areas of performance. See Displaying-the-Exception-Monitor-member-list for more information.

The following example illustrates how you might use the Exception Monitor to gather information about a particular aspect of system performance.

Suppose that, for resource-planning purposes, you want to record how often CPU2 on SYSA is utilized beyond 75 percent of its capacity. After accessing the Exception Monitor on SYSA, follow these steps:

  1. Create a control statement member called PWSCPMC2.
  2. Select the CPU sampler by typing S next to it.
  3. Set a threshold for CPU2 by typing 75 next to the CPU2 field on the CPU Sampler screen.
  4. To monitor channel path utilization and the paging subsystem simultaneously, add the samplers CHA and PAG to PWSCPMC2 as well.
  5. Start the Exception Monitor with the PWSCPMC2 control statement member.The Exception Monitor will now monitor the CPUs, channel paths, and paging subsystem according to the thresholds that you set. When CPU2 is utilized above 75 percent of its capacity, the Exception Monitor sends a warning message to both the WARN view and the z/OS console.
    The next section tells you how to start the Exception Monitor.

 

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