PRTG Manual: Probe Health Sensor

The Probe Health sensor monitors internal PRTG parameters. It shows the status of the probe system.

The sensor checks various parameters of the probe system that can affect the quality of the monitoring results:

  • Health: This index value sums up the probe state as a value between 100% (healthy) and 0% (failing). Investigate frequent or repeated health values below 100%.
  • Probe Process CPU Load: This channel shows the CPU load in percent that the probe process causes. Extensive CPU load can lead to false, incomplete, and incorrect monitoring results. This value should usually 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 channel settings.
  • Handles: This is a counter for the data structures of the operating system. It is responsible for internal resource management. Investigate obviously increasing values that occur repeatedly.
  • Interval Delay non-WMI&SNMP: This channel shows the interval delay in percent for all sensors that are not of the type Simple Network Management Protocol (SNMP) or Windows Management Instrumentation (WMI). If this value is above 0%, try to increase the scanning intervals or distribute your sensors among probes.
  • Interval Delay SNMP: This channel shows the interval delay in percent for SNMP sensors. If this value is above 0%, there are probably too many SNMP v3 sensors that are very slow. In this case, try to increase the scanning intervals or distribute the sensors among probes.
  • Interval Delay WMI: This channel shows the interval delay in percent for WMI sensors. If this value is above 0%, WMI sensors were not able to check the target device according to their interval. 100% means that WMI sensors are checked with twice their interval on average. For values above 0%, try to increase the scanning intervals or distribute the sensors among probes to keep the number of WMI sensors per probe below 120 (with a 60-second scanning interval) or 600 (with a 300-second scanning interval).
  • Lost Flow Packets: This channel shows the percentage of lost xFlow (NetFlow, jFlow, sFlow, IPFIX) packets. The higher this value, the less xFlow packages PRTG can handle. Usually, this value should be 0%. Investigate increasing values.
  • Memory Usage: This channel shows the amount of memory that is used by the PRTG probe service as reported by the memory manager. Investigate obviously increasing values that occur repeatedly. If the value is constantly above 2 GB, this indicates that PRTG runs at its limits. In this case, you should distribute some sensors among remote probes.
  • Message Queue: This channel shows the number of monitoring results that have not been processed by the core yet. This value should usually stay below 1/10 of the sensor count.
  • Open Requests: This channel shows the number of 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. This value can increase with heavy load. Usually, the number should not exceed 100.
  • 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 the available memory on the probe system). If necessary, reduce the number of Toplists or distribute them among 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 sonde
  • German: Zustand der Probe
  • Japanese: プローブ正常性
  • Portuguese: Funcionamento da sonda
  • Russian: Работоспособность зонда
  • Simplified Chinese: 探针健康状况
  • Spanish: Salud de sonda

Remarks

Basic Sensor Settings

Click the Settings tab of a sensor to change its settings.

icon-i-round-blueUsually, a sensor connects to the IP Address or DNS Name of the parent device on which you created the sensor. See the device settings for details. For some sensors, you can explicitly define the monitoring target in the sensor settings. See below for details on available settings.

Setting

Description

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. Confirm each tag with the Spacebar key, a comma, or the Enter key. You can use tags to group objects and use tag-filtered views later on. Tags are not case-sensitive. Tags are automatically inherited. You can add additional tags to the sensor.

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

There are default tags that are automatically predefined in a sensor's settings when you add a sensor. See section Default Tags below.

Priority

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

Default Tags

probehealthsensor

Sensor Display

Setting

Description

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 is always displayed below the sensor's name. The available options depend on what channels are available for this sensor.

icon-i-round-blueYou can set a different primary channel later by clicking the pin symbol of a channel on the sensor's Overview tab.

Graph Type

Define how different channels are shown for this sensor:

  • Show channels independently (default): Show a 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 generates a graph that visualizes the different components of your total traffic.
    icon-i-round-blueThis option cannot be used in combination with manual Vertical Axis Scaling (available in the channel settings).

Stack Unit

This field is only visible if you enable Stack channels on top of each other as Graph Type. Select a unit from the list. All channels with this unit are 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 of the following settings are inherited from objects that are higher in the hierarchy and should be changed there if necessary. Often, best practice is to change them centrally in the root group settings. For more information, see section Inheritance of Settings. To change a setting for this object only, disable inheritance by clicking the button next to inherit from under the corresponding setting name. You then see the options described below.

Scanning Interval

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

Setting

Description

Scanning Interval

Select a scanning interval (seconds, minutes, or hours). The scanning interval determines the amount of time that 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 the sensor has time to reach and check a device again in case a sensor query fails. Depending on the option that you select, the sensor can try to reach and check a device again several times before the sensor shows a Down status. This can avoid false alarms if the monitored device only has temporary issues. For previous scanning intervals with failed requests, the sensor shows a Warning status. Choose from:

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

icon-i-round-blueSensors that monitor via Windows Management Instrumentation (WMI) always wait at least one scanning interval before they show a Down status. It is not possible to immediately set a WMI sensor to a Down status, so the first option does not apply to these sensors. All other options can apply.

icon-i-round-blueIf you define error limits for a sensor's channels, the sensor immediately shows a Down status. No "wait" option applies.

icon-i-round-blueIf a channel uses lookup values, the sensor immediately shows a Down status. No "wait" options apply.

Access Rights

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

Setting

Description

User Group Access

Define the user groups that have access to the sensor. You see a table with user groups and group access rights. The table contains all user groups in your setup. For each user group, you can choose from the following group access rights:

  • Inherited: Inherit the access rights settings of the parent object.
  • No access: Users in this user group cannot see or edit the sensor. The sensor neither shows up in lists nor in the device tree.
  • Read access: Users in this group can see the sensor and view its monitoring results. They cannot edit any settings.
  • Write access: Users in this group can see the sensor, view its monitoring results, and edit its settings. They cannot edit its access rights settings.
  • Full access: Users in this group can see the sensor, view its monitoring results, edit its settings, and edit its access rights settings.

icon-square-cyanFor more details on access rights, see section Access Rights Management.

Channel Unit Configuration

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

Setting

Description

Channel Unit Types

For each type of 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-round-blueCustom channel types can be set on sensor level only.

More

icon-square-blueKNOWLEDGE BASE

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

Edit Channels

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

Notification Triggers

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

Others

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

Sensor Settings Overview

For information about sensor settings, see the following sections: