PRTG Manual: Probe Health Sensor

The Probe Health sensor monitors internal PRTG parameters. It shows the status of the PRTG probe (either for the local probe, the hosted probe, a remote probe, or a cluster probe).

It checks various parameters of your PRTG system that can affect the quality of the monitoring results:

  • Health: This index value sums up the probe state into a value between 100% (healthy) and 0% (failing). Frequent or repeated health values below 100% should be investigated.
  • Probe Process CPU Load: This channel shows the current percentage CPU load that the probe process causes. Extensive CPU load can lead to false, incomplete, and incorrect monitoring results. This value usually should stay below 50%.
  • Data Storage Free: This channel shows the free disk space on the probe system. PRTG dynamically sets limits for this channel. You can manually override these limits in the sensor channel settings.
  • Handles: This is a counter for the data structures of the operating system. It is responsible for internal resource management. Repeated obviously increasing values should be investigated.
  • Interval Delay non-WMI&SNMP: This channel shows the percentage interval delay for all sensor types that are not of the type SNMP or WMI. If this value is over 0%, try to increase the scanning intervals or distribute your sensors over multiple probes.
  • Interval Delay SNMP: This channel shows the percentage interval delay for SNMP sensors. If this value is above 0%, there are probably too many very slow SNMP V3 sensors. In this case, try to increase the monitoring intervals or distribute the sensors over several probes.
  • Interval Delay WMI: This channel shows the percentage interval delay for WMI sensors. If this value is above 0%, WMI sensors could not check the target device according to their interval. 100% means that WMI sensors on the average are checked with twice their interval. For values above 0% try to increase the monitoring intervals or distribute the sensors over several probes to keep the number of WMI sensors per probe below 120 (with 60 seconds interval) or 600 (with 300 seconds interval).
  • Lost Flow Packets: This channel shows the percentage of lost flow packets. The higher this value, the less flow packages PRTG can handle. Usually, this value should be 0%. Investigate increasing values.
  • Memory Usage: This channel shows the amount of memory being used by the PRTG probe service as reported by the memory manager. Repeated obviously increasing values should be investigated. If the value is constantly above 2 GB this indicates that PRTG runs at its limits. In this case you should distribute some sensors to Remote Probe.
  • Message Queue: This channel shows the number of monitoring results from the probe that have not been processed yet by the core. This value usually should stay below 1/10 of the sensor count.
  • Open Requests: This channel shows the number of currently active monitoring requests. This value should stay below the maximum of 500 open requests.
  • Syslog Buffer: This channel shows the number of buffered syslog packages. Usually, this value should be 0 (or very low). Investigate increasing values.
  • Threads: This channel shows the number of program parts that are running simultaneously currently. This value can increase with heavy load. The number should not exceed 100 in normal operation.
  • Toplist Memory: This channel shows the amount of RAM that the Toplists on this probe are using. Stay below 1 GB memory usage (depending on available memory on the probe system). If necessary, reduce the number of toplists or distribute them on multiple probes.
  • Trap Buffer: This channel shows the number of buffered SNMP traps. Usually, this value should be 0 (or very low). Investigate increasing values.
Probe Health Sensor
Probe Health Sensor

Sensor in Other Languages

Dutch: Probe Status, French: État de la probe, German: Zustand der Probe, Japanese: プローブヘルス, Portuguese: Funcionamento da sonda, Russian: Работоспособность зонда, Simplified Chinese: 探针健康状况, Spanish: Salud de sonda

Remarks

Sensor Settings

On the details page of a sensor, click the Settings tab to change its settings.

icon-i-roundUsually, a sensor connects to the IP Address or DNS Name of the parent device where you created this sensor. See the Device Settings for details. For some sensor types, you can define the monitoring target explicitly in the sensor settings. Please see below for details on available settings.

Basic Sensor Settings

Sensor Name

Enter a meaningful name to identify the sensor. By default, PRTG shows this name in the device tree, as well as in alarms, logs, notifications, reports, maps, libraries, and tickets.

Parent Tags

Shows Tags that this sensor inherits from its parent device, group, and probe. This setting is shown for your information only and cannot be changed here.

Tags

Enter one or more Tags, separated by spaces or commas. You can use tags to group sensors and use tag–filtered views later on. Tags are not case sensitive. We recommend that you use the default value.

You can add additional tags to the sensor if you like. Other tags are automatically inherited from objects further up in the device tree. These are visible above as Parent Tags.

icon-i-roundIt is not possible to enter tags with a leading plus (+) or minus (-) sign, nor tags with round parentheses (()) or angle brackets (<>).

Priority

Select a priority for the sensor. This setting determines where the sensor is placed in sensor lists. Top priority is at the top of a list. Choose from one star (low priority) to five stars (top priority).

Sensor Display

Primary Channel

Select a channel from the list to define it as the primary channel. In the device tree, the last value of the primary channel will always be displayed below the sensor's name. The available options depend on what channels are available for this sensor.

icon-i-roundYou can set another primary channel later by clicking the pin symbol of a channel in the sensor's Overview tab.

Graph Type

Define how different channels will be shown for this sensor.

  • Show channels independently (default): Show an own graph for each channel.
  • Stack channels on top of each other: Stack channels on top of each other to create a multi-channel graph. This will generate an easy-to-read graph that visualizes the different components of your total traffic.
    icon-i-roundThis option cannot be used in combination with manual Vertical Axis Scaling (available in the Sensor Channels Settings settings).

Stack Unit

This setting is only available if stacked graphs are selected above. Choose a unit from the list. All channels with this unit will be stacked on top of each other. By default, you cannot exclude single channels from stacking if they use the selected unit. However, there is an advanced procedure to do so.

Inherited Settings

By default, all following settings are inherited from objects higher in the hierarchy and should be changed there, if necessary. Often, best practice is to change them centrally in the Root group's settings, see section Inheritance of Settings for more information. To change a setting only for this object, disable inheritance by clicking the button next to inherit from under the corresponding setting name. You will then see the options described below.

Scanning Interval

Click inherited_settings_button to disrupt the inheritance. See section Inheritance of Settings for more information.

Scanning Interval

Select a scanning interval (seconds, minutes, or hours) from the list. The scanning interval determines the time the sensor waits between two scans. You can change the available intervals in the system administration on PRTG on premises installations.

If a Sensor Query Fails

Define the number of scanning intervals that a sensor has time to reach and check a device again in case a sensor query fails. The sensor can try to re-reach and check a device several times, depending on the option you select here, before it will be set to a Down status. This helps you avoid false alarms if the monitored device has only temporary issues. For previous scanning intervals with failed requests, the sensor will show a Warning status. Choose between:

  • Set sensor to "down" immediately: The sensor will show an error immediately after the first failed request.
  • Set sensor to "warning" for 1 interval, then set to "down" (recommended): After the first failed request, the sensor will show a yellow warning status. If the following request also fails, the sensor will show an error.
  • Set sensor to "warning" for 2 intervals, then set to "down": Show an error status only after three consecutively failed requests.
  • Set sensor to "warning" for 3 intervals, then set to "down": Show an error status only after four consecutively failed requests.
  • Set sensor to "warning" for 4 intervals, then set to "down": Show an error status only after five consecutively failed requests.
  • Set sensor to "warning" for 5 intervals, then set to "down": Show an error status only after six consecutively failed requests.

icon-i-roundSensors that monitor via Windows Management Instrumentation (WMI) always wait at least one scanning interval until they show an error. It is not possible to set a WMI sensor to "down" immediately, so the first option will not apply to these sensor types. All other options can apply.

icon-i-roundIf a sensor has defined error limits for channels, it will always show a Down status immediately, so no "wait" option will apply.
 

icon-i-roundIf a channel uses lookup values, it will always show a Down status immediately, so no "wait" options will apply.

Access Rights

Click inherited_settings_button to disrupt the inheritance. See section Inheritance of Settings for more information.

User Group Access

Define which user group(s) will have access to the object you're editing. A table with user groups and types of access rights is shown: It contains all user groups from your setup. For each user group, you can choose from the following access rights:

  • Inherited: Use the access rights settings of the parent object.
  • None: Users in this group cannot see or edit the object. The object neither shows up in lists nor in the device tree. Exception: If a child object is visible to the user, the object is visible in the device tree, though not accessible.
  • Read: Users in this group can see the object and review its monitoring results.
  • Write: Users in this group can see the object, review its monitoring results, and edit the object's settings. They cannot edit access rights settings.
  • Full: Users in this group can see the object, review its monitoring results, edit the object's settings, and edit access rights settings.

You can create new user groups in the System Administration—User Groups settings. To automatically set all objects further down in the hierarchy to inherit this object's access rights, set a check mark for the Revert children's access rights to inherited option.

icon-book-arrowsFor more details on access rights, see the section User Access Rights.

Channel Unit Configuration

Click inherited_settings_button to disrupt the inheritance. See section Inheritance of Settings for more information.

Channel Unit Types

For each type of sensor channel, define the unit in which data is displayed. If defined on probe, group, or device level, these settings can be inherited to all sensors underneath. You can set units for the following channel types (if available):

  • Bandwidth
  • Memory
  • Disk
  • File
  • Custom

icon-i-roundCustom channel types can be set on sensor level only.

More

Knowledge Base: My probe system is running out of disk space. What can I do?

Edit Sensor Channels

To change display settings, spike filter, and limits, switch to the sensor's Overview tab and click the gear icon of a specific channel. For detailed information, see the Sensor Channels Settings section.

Notifications

Click the Notifications tab to change notification triggers. For detailed information, see the Sensor Notifications Settings section.

Others

For more general information about settings, see the Object Settings section.

Sensor Settings Overview

For information about sensor settings, see the following sections: