Customizing check exceptions with dynamically varying severity

Some checks provide the capability of issuing check exception messages with a dynamically varying severity level, which gives you more control over how exception messages are issued and handled. For example, you might use the dynamic severity function for checks that inspect a system setting value and compare it against a threshold. As the value approaches the high threshold, the check can vary the severity of the exception, depending on how close to the threshold the value is. Some checks that support dynamic severity are:

CHECK(IBMASM,ASM_PLPA_COMMON_SIZE)
CHECK(IBMASM,ASM_LOCAL_SLOT_USAGE)
CHECK(IBMASM,ASM_PLPA_COMMON_USAGE)
CHECK(IBMVSM,VSM_CSA_THRESHOLD)
CHECK(IBMVSM,VSM_SQA_THRESHOLD)

Example of using dynamic severity for a check: In this example, check VSM_CSA_THRESHOLD looks at the systems's level of common service area (CSA) storage level. If the ultimate emergency high level threshold for CSA usage is 95%, you might establish criteria for low, medium and high severity check exceptions based on CSA usage as follows:

CSA usage at 60% is LOW severity
CSA usage at 80% is MED severity
CSA usage at 95% is HI severity

The advantage of staging the severity like this is that you get a little more flexibility and react-time than simply having one threshold established at CSA usage of 95%.

How does the check know what severity exception to issue when using dynamic severity? The check knows what severity exception to issue because you'll tell it ahead of time, using the check parameters. For example, use the example we've provided, we might define the following check parameters for the VSM_CSA_THRESHOLD check:

CSA_LOW(60%) - to send a low severity exception message for a CSA usage between 60% and 79%
CSA_MED(80%) - to send a medium severity exception message for a CSA usage between 80% to 94%
CSA_HIGH(95%) - to send a high severity exception message for CSA usage of 95% and above.

The check looks at the CSA usage on the system, and then uses the check parameters defined to determine what check severity to use when issuing an exception message.

It can be confusing to figure out whether a larger/higher parameter value corresponds to a higher severity or not. To make things even more confusing, checks such as the VSM_CSA_THRESHOLD check have it both ways! If you specify the parameter as a percent, then a bigger percentage corresponds to a higher severity. If you specify the parameter as a number, this applies to the amount of storage remaining and a lower number corresponds to a higher percentage. Read the parameter descriptions carefully.

For information about writing a check that exploits dynamic severity, see Writing a check with dynamic severity levels.