Event Triggers for Counters

NetCrunch allows for the setting up of various threshold conditions on performance data regardless of origin. This works for all performance data channels, from SNMP data to data received through the REST API.

Thresholds

Thresholds trigger an event when a value is crossing a given border. Depending on the direction's change, it can be a rising or falling threshold condition.

A simple threshold specifies only the threshold value and the direction.

Rising threshold example:

% Processor Utilization > 50%

Falling threshold example:

% Free Disk Space < 10%

Hysteresis

Hysteresis can be used to avoid generating too many threshold events on fast-changing values. This is done by setting an additional resetting value.

Example:

Trigger on

% Processor Utilization > 50%

Reset if

value <= 45%

Thresholds can be configured based on the last value or the average value calculated over a specified time range.

Flat Value Trigger

This trigger generates an event when the counter has (or has not) the same value in the given period.

Example:

% Processor Time = 25 for the last 5 samples

State Trigger

This trigger generates an event when the monitored value changes from one value to another. You need to specify at least one value.

Example:

Network Card Error State changes from <any> to 5

The event can be reset when the value changes to the previous state or any other value.

Value Missing/Exists Trigger

This trigger generates an event if value exists or is missing (can't be read or received) in a given time range.

Example:

There might be no value until an error occurs, so the program can react to a value exists condition instead.

Delta Trigger

This trigger alerts you when the current counter value keeps growing or decreasing by a given value. You can also define the opposite condition when the counter is not growing or decreasing as expected. Delta is the difference between the last and the previous value.

Example:

 Device Internal Timer Delta    < 1 

Deviation Threshold Trigger

This trigger allows you to specify how a counter value can differ from the calculated average over a given period. The deviation can be set as a percentage or by absolute value.

Example:

Trigger on

% Round Trip Time Deviation > 10%

Reset if

Deviation < 8%

Calculate an average for the last

3 samples

Range Trigger

This trigger simplifies configuration. Instead of two separate thresholds for a low and high boundary, you can specify a range. The event triggers if a counter value is in the range or outside the range. Additionally, you can specify the reset tolerance value.

Example:

Trigger on

Server Room Temperature is outside the range [ 20 ... 22 ]

Reset if

Falls in the range with a margin of 2

Baseline Threshold Trigger

This trigger allows setting thresholds for deviation from observed baseline data. The program collects baseline data over a week and stores them for reference. The baseline is calculated for each hour and each day of the week.

The user can specify the allowed deviation from the baseline value (by a number or a percentage).

Example:

Trigger on

Server Room Temperature deviation from baseline > 1

Limit Trigger

This trigger allows you to set an alert on a limit on the aggregated value of a given parameter. For example, it might be the number of bytes transmitted per day or week.

It works to counter-represent value per second or accumulate values (increasing).

Available periods:

• current hour
• current day
• week, starting on Monday - Sunday
• month, starting on a specified month-day

averagebaselineeventhysteresislimitperformancerangethresholdtriggers