<%NUMBERING1%>.<%NUMBERING2%>.<%NUMBERING3%> PRTG Manual: Similar Sensors

With PRTG, you can detect relationships between different components in your network. For example, you can detect extraordinarily high CPU load correlating with extraordinarily high traffic at a specific time of a day or week. This might give you a hint to further investigate that part of your network.

What is Similarity?

The similarity calculation is based on the values that are saved in the history of sensors. If measured values change in the same way, the similar sensors analysis will detect it and show you the sensors that it found similar data relations for. PRTG will show all sensors that reach 85 % to 100 % similarity.

We implemented the similar sensors analysis as a heuristic calculation designed to show interconnections and correlations in your network that maybe you were not even aware of. The analysis is completely automated and sensor type agnostic. It is based on mathematics and fuzzy logic and optimizes your sensor usage by tracking redundant monitoring of some aspects of your system.

Similar Sensors Analysis in PRTG

You can adjust the depth of similar sensors analysis or turn it off in System Administration—Monitoring. You can also enable or disable the similarity analysis for specific probes, groups, and devices and specify inheritance in the corresponding object settings, section Automatic Monitoring Analysis.

There are two options to view similar sensors:

The overview page of sensors contains a similar sensors section. PRTG lists channels there that show similarities to channels of the current sensor.
In addition, you can call a similar sensors overview page via Sensors | Similar Sensors Overview from the main menu.

To edit the list of the similar sensors results, use the available filters.

Similar Sensors (Sensor Overview Tab)

Probe, group, device, and sensor pages have tabs that you can use to navigate between the different options. For example, you can view your network's status, view monitoring results, or change settings.

Tabs Bar on Sensor Pages

On the overview tab of a sensor, PRTG lists channels that show similarities to channels of the currently selected sensor. The table is empty if PRTG detects no similarities regarding the selected sensor.

PRTG shows similar sensors here when channels have 85% similarity or more. The similar sensors analysis saves up to 15 entries per sensor.

Similar Sensors Section on a Sensor's Overview Tab

The similar sensors section provides the following information:

Similar Sensors
Similarity	Shows a measurement of similarity between two channels in percent.
Channel	Shows a channel of the currently selected sensor.
Similar Channel	Shows a channel of another sensor similar to a channel of the currently selected sensor (the one in the "Channel" column in the same row).

PRTG does not show the similar sensors section when the analysis is off or when you have exceeded 1,000 sensors and selected the automatic analysis depth option. You will see a notice in this case.

Similar Sensors Overview (Sensors Menu)

This page shows the results of the similar sensors analysis from the entire monitoring database. PRTG lists all channels with similarities to another one here. Above the table, you have several filter options to display similar sensors as you need it. Choose the object of interest, the degree of similarity, and if you want to, display back references.

For more details, see also section Working with Table Lists.

PRTG shows similar sensors here when channels have at least 85% similarity. Furthermore, the analysis saves up to 15 entries per sensor.

Similar Sensors Overview

You can sort the list by clicking the column headers. The similar sensors overview page provides the following information:

Similar Sensors Overview
Original Channel	Shows channels that other channels are compared to. Click the column header to sort the list according to the order in the device tree in ascending or descending order.
Similarity	Shows a measurement of similarity between two channels in percent. Click the column header to sort the list according to the similarities in ascending or descending order.
Similar Channel	Shows a channel compared to the original channel. Click the column header to sort the list according to the order in the device tree in ascending or descending order.

PRTG does not show the similar sensors overview option in the main menu if you turned off the analysis or if you have exceeded 1,000 sensors and selected the automatic analysis depth option.

Adjust the Similar Sensors Overview to Your Needs

You can use various filters to adjust the displayed results of the similar sensors analysis. Click Show Filters and edit the filters that show up.

Filters for the Similar Sensors Analysis

Similar Sensors Filters
Sensors Related To	Select the device, probe, or group that you want the similar sensors analysis to cover. This way, you can apply the analysis to the parts of your network that you are interested in.
With a Maximum Similarity Of	Select a degree of similarity from 85 % to 100 %.
Inverted Relationships	If you select Show, PRTG shows all similarity relationships, that is, A matches B and B matches A. If you select Hide, PRTG only shows A matches B relationships. This reduces the number of displayed similar sensors.

Similar Sensors Filters

Sensors Related To

Select the device, probe, or group that you want the similar sensors analysis to cover. This way, you can apply the analysis to the parts of your network that you are interested in.

With a Maximum Similarity Of

Select a degree of similarity from 85 % to 100 %.

Inverted Relationships

If you select Show, PRTG shows all similarity relationships, that is, A matches B and B matches A.

If you select Hide, PRTG only shows A matches B relationships. This reduces the number of displayed similar sensors.

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