Create a Threshold
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Click the gear icon in the top-right.
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Under Performance Measurement, choose Configure Thresholds.
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A screen with a list of preconfigured threshold groups appears. We will work with netsnmp. For information on how to create a threshold group, see Create a Threshold Group.
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Click Edit beside the netsnmp group.
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Click Create New Threshold at the bottom of the Basic Thresholds area of the screen.
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Set the following information and click Save:
| Field | Description | Default |
|---|---|---|
Type |
Triggers an event when the data source value equals or exceeds the threshold value, and re-arms when it equals or drops below the re-arm value. |
high |
Datasource |
Name of the data source you want to threshold against. For this tutorial, we have provided the data source for logged-in users. For information on how to determine a metric’s data source, see Determine the data source. |
hrSystemNumUsers |
Datasource label |
Optional text label. Not required for this tutorial. |
leave blank |
Value |
The value above which we want to trigger an event. In this case, we want to trigger an event when the number of logged-in users exceeds two. |
2 |
Re-arm |
The value below which we want the system to re-arm. In this case, once the number of logged-in users falls below two. |
2 |
Trigger |
The number of consecutive times the threshold value can occur before the system triggers an event. Since our default polling period is 5 minutes, a value of 3 means Meridian would create a threshold event if there are more than 2 users for 15 minutes. |
3 |
Description |
Optional text to describe your threshold. |
leave blank |
Triggered UEI |
A custom unique event identifier (UEI) sent into the events system when the threshold is triggered. A custom UEI for each threshold makes it easier to create notifications. If left blank, it defaults to the standard thresholds UEIs. |
leave blank |
Re-armed UEI |
A custom unique event identifier (UEI) sent into the events system when the threshold is re-armed. |
leave blank |
Test the threshold
To test the threshold we just created, log a second person into the node you are monitoring. Navigate to the Events page. You should see an event that indicates your threshold triggered when more than one user logged in.
Log out the second user. The Events page should indicate that the system has re-armed.
Create a threshold for CPU use
This procedure describes how to create an expression-based threshold when the five-minute CPU load average metric reaches or goes above 70% for two consecutive measurement intervals. Expression-based thresholds are useful when you need to threshold on a percentage, not the actual value of the data collected.
| Expression-based thresholds work only if the data sources in question are in the same directory. |
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Click the gear icon in the top-right.
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Under Performance Measurement, choose Configure Thresholds.
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Click Edit beside the netsnmp group.
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Click Create New Expression-based Threshold.
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Fill in the following information:
Field Description Default Type
Triggers an event when the data source value equals or exceeds the threshold value, and re-arms when it equals or drops below the re-arm value.
high
Expression
Divides the five-minute CPU load average by 100 (to obtain the effective load average*), which is then divided by the number of CPUs. This value is then multiplied by 100 to provide a percentage.
(* SNMP does not report in decimals, which is why the expression divides the loadavg5 by 100.)
((loadavg5 / 100) / CpuNumCpus) * 100
Datasource type
The type of data source from which you are collecting data.
node
Datasource label
Optional text label. Not required for this tutorial.
leave blank
Value
Trigger an event when the five-minute CPU load average goes above 70%.
70
Re-arm
Re-arm the system when the five-minute CPU load average drops below 50%.
50
Trigger
The number of consecutive times the threshold value can occur before the system triggers an event. In this case, when the five-minute CPU load average goes above 70% for two consecutive polling periods.
2
Description
Optional text to describe your threshold.
Trigger an alert when the five-minute CPU load average metric reaches or goes above 70% for two consecutive measurement intervals.
Triggered UEI
A custom unique event identifier (UEI) sent into the events system when the threshold is triggered. A custom UEI for each threshold makes it easier to create notifications. If left blank, it defaults to the standard thresholds UEIs.
leave blank
Re-armed UEI
A custom unique event identifier (UEI) sent into the events system when the threshold is re-armed.
leave blank
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Click Save.