PRTG Manual: Probe Health Sensor
The Probe Health sensor monitors internal PRTG parameters. It shows the status of the probe system (either of a local probe, a hosted probe, a remote probe, or a cluster probe).
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). Frequent or repeated health values below 100% should be investigated.
- Probe Process CPU Load: This channel shows the current 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 sensor channel settings.
- Handles: This is a counter for the data structures of the operating system. It is responsible for internal resource management. Obviously increasing values that occur repeatedly should be investigated.
- 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 multiple 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 multiple 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 multiple 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. Obviously increasing values that occur repeatedly 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 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 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 currently 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 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
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
- PRTG automatically creates this sensor. You cannot delete it.
- You can only create this sensor on a probe device (either a local probe, a remote probe, or a cluster probe).
- Knowledge Base: My probe system is running out of disk space. What can I do?
Click the Settings tab of a sensor to change its settings.
Usually, 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.
Basic Sensor Settings |
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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. There are default tags that are automatically predefined in a sensor's settings when you add a sensor. See section Default Tags below. 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.
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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). |
probehealthsensor
Sensor Display |
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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.
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Graph Type |
Define how different channels are shown for this sensor:
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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. |
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's 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 |
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Click |
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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:
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Access Rights |
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Click |
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User Group Access |
Define the user groups that have access to the selected object. 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:
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.
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Channel Unit Configuration |
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Click |
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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):
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Knowledge Base: My probe system is running out of disk space. What can I do?
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.
Click the Notification Triggers tab to change notification triggers. For detailed information, see section Sensor Notification Triggers Settings.
For more general information about settings, see section Object Settings.
For information about sensor settings, see the following sections:
