Setting a threshold for a metric that is being collected by a monitor allows you to be notified and, optionally, to specify actions to be taken when a certain value (called the trigger value) is reached. You can also specify actions to be taken when a second value (called the reset value) is reached.
For example, when you create a system monitor, you can specify an i5/OS™ command that stops any new jobs from starting when CPU utilization reaches 90% and another i5/OS command that allows new jobs to start when CPU utilization falls to less than 70%.
For some metrics, it is appropriate to specify a reset value, which resets the threshold and allows it to be triggered again when the trigger value is reached. For those thresholds, you can specify a command to be run when the reset value is reached. For other metrics (such as the File Status metric and the Text metric on file monitors, and any message set on a message monitor), you can specify to automatically reset the threshold when the trigger command is run.
You can set up to two thresholds for each metric that the monitor is collecting. Thresholds are triggered and reset based on the value at the time the metric collection is made. Specifying a higher number of collection intervals in the Duration field helps to avoid unnecessary threshold activity due to frequent spiking of values.
You can also choose to add an event to the Event Log whenever the trigger value or the reset value is reached.
On the New Monitor - Metrics page, the threshold tabs provide a place for you to specify a threshold value for each metric that you have selected to monitor. For example, if you are creating a job monitor, you can set your threshold values in the following ways depending on the type of metric you have selected:
| Job Count | When you define a threshold, you can specify a command to run on the
endpoint system when the threshold is triggered. For example, selecting will trigger
the threshold whenever the monitor detects more than 25 jobs running during
the number of collection intervals you specify for Duration. You can then specify a command to be run on the endpoint system when the monitor detects more than 25 jobs. Enter the command name and click Prompt for assistance in specifying the parameters for the command. For more detailed information and examples of specifying commands to be run when thresholds are triggered, see the performance scenarios topic. Enable reset is optional, and cannot be selected until a trigger is defined. You can also specify a command to be run on the endpoint system when the threshold is reset. |
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| Job Log Message | You must select Trigger when any of the following messages
are sent to the job log before you can specify the conditions
to trigger a threshold. You can specify messages to monitor for based on any
combination of Message ID, Type, and Minimum severity. Each row in the Job
Log Message table shows a combination of criteria that must be met for a message
to trigger a threshold. A threshold will be triggered if it meets the criteria
in at least one row. Use the online help to specify the conditions to trigger
a threshold. Be careful to monitor the smallest number of jobs that will give you the information you need. Monitoring a large number of jobs for job log messages may have a performance impact on your system. You can specify a command to be run on the endpoint system when the threshold is triggered. Enter the command name and click Prompt for assistance in specifying the parameters for the command. Be sure to click the Collection Interval tab to specify how often you want the monitor to check for job log messages. A message trigger can only be manually reset. You can specify a command to be run on the endpoint system when the threshold is reset. When you reset the monitor, you always have the option to reset without running the specified command. |
| Job Status | On the Metrics - General tab, select the statuses
that you want to monitor for. Click the Metrics - Status Threshold tab
to specify the conditions to trigger a threshold. You must select Trigger
when job is in any selected status before you can specify the
conditions to trigger a threshold. The threshold is triggered whenever the
monitor detects that the job is in any selected status for the number of collection
intervals you specify for Duration. You can then specify a command to be run on the endpoint system when the threshold is triggered. Enter the command name and click Prompt for assistance in specifying the parameters for the command. Reset when job is not in selected statuses is optional, and cannot be selected until a trigger is defined. You can specify a command to be run on the endpoint system when the threshold is reset. |
| Job Numeric Values | When you define the threshold, you can specify a command to run on
the endpoint system when the threshold is triggered. For example, selecting for the Transaction Rate metric will trigger the threshold
whenever the monitor detects more than 101 transactions per second on any
of the selected jobs during the number of collection intervals you specify
for Duration. You can then specify a command to be run on the endpoint system when the monitor detects more than 101 transactions per second. Enter the command name and click Prompt for assistance in specifying the parameters for the command. Enable reset is optional, and cannot be selected until a trigger is defined. You can also specify a command to be run on the endpoint system when the threshold is reset. |
| Summary Numeric Values (total for all jobs) | When you define a threshold, you can specify a command to run on the
endpoint system when the threshold is triggered. For example, selecting for the Transaction Rate metric will trigger the threshold
whenever the monitor detects more than 1001 transactions per second on all
of the selected jobs during the number of collection intervals you specify
for Duration. You can then specify a command to be run on the endpoint system when the monitor detects more than 1001 transactions per second. Enter the command name and click Prompt for assistance in specifying the parameters for the command. Enable reset is optional, and cannot be selected until a trigger is defined. You can also specify a command to be run on the endpoint system when the threshold is reset. |
For more information about these and other Management Central tasks and topics, refer to the detailed task help that is available from the iSeries™ Navigator window. Click Help from the menu bar and select .