<%NUMBERING1%>.<%NUMBERING2%>.<%NUMBERING3%> PRTG Manual: WMI Memory Sensor

The WMI Memory sensor monitors available (free) system memory on Windows systems using Windows Management Instrumentation (WMI). It shows the available memory in percent and in total.

For this sensor type credentials for Windows systems must be defined for the device you want to use the sensor on.

Note: Sensors using the Windows Management Instrumentation (WMI) protocol have high impact on the system performance! Try to stay below 200 WMI sensors per probe. Above this number, please consider using multiple Remote Probes for load balancing.

For a general introduction to the technology behind WMI, please see Monitoring via WMI section.

Add Sensor

The Add Sensor dialog appears when adding a new sensor on a device manually. It only shows the setting fields that are imperative for creating the sensor. Therefore, you will not see all setting fields in this dialog. You can change all settings in the sensor's Settings tab later.

Sensor Settings

On the sensor's details page, click on the Settings tab to change settings.

Note: If not set explicitly in a sensor's settings, it will connect to the IP Address or DNS Name defined in the settings of the parent device the sensor is created on.

Basic Sensor Settings

Sensor Name

Enter a meaningful name to identify the sensor. The name will be shown by default in the device tree and in all alarms.

Tags

Enter one or more tags, separated by space or comma. You can use tags to group sensors and use tag-filtered views later on. Tags are not case sensitive. We recommend using the default value. You can add additional tags to it, if you like. Other tags are automatically inherited from objects further up in the device tree. Those are not visible here.

Priority

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

WMI Alternative Query

Errors and Invalid Data

This is an extended help field only. PRTG's WMI sensors are equipped with the most efficient and accurate WMI queries. However, Microsoft has changed (and will continue to do that in the future) some WMI classes over the various Windows/ServicePack/patchlevel versions, resulting in errors like "class not valid" or "invalid data". Wherever possible, PRTG features an alternative query that might work in your specific configuration. When you keep getting errors for this sensor, please try enabling the alternative query method below.

Alternative Query

Choose the method PRTG uses to query via WMI. For compatibility reasons, you can enable an alternative query method. We recommend using the default value. You can choose between:

  • Use default (recommended): Use PRTG's standard method to query WMI. This is the best setting in most cases.
  • Use alternative (if default does not work): Use an alternative method to query WMI. If you keep getting errors with the default setting, please try this setting.

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 underneath the sensor's name. The available options depend on what channels are available for this sensor. Note: You can set another primary channel later by clicking on the pin symbol of a channel in the sensor's overview tab.

Chart 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 which visualizes the different components of your total traffic. Note: This 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. To change a setting for this object, disable inheritance by clicking on the check mark symbol in front of the respective setting name. You will then see the options described below.

Scanning Interval

Scanning Interval

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

When a Sensor Reports an Error

With this setting, you can define the number of scanning intervals a sensor has to report an error until the sensor will be set to a Down status. The sensor can try reaching a device several times, depending on your setup you can specify here, to help 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 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": The sensor will only show an error status after three failed requests in a row.
  • Set sensor to "warning" for 3 intervals, then set to "down": The sensor will only show an error status after four failed requests in a row.
  • Set sensor to "warning" for 4 intervals, then set to "down": The sensor will only show an error status after five failed requests in a row.
  • Set sensor to "warning" for 5 intervals, then set to "down": The sensor will only show an error status after six failed requests in a row.

Note: Sensors that monitor via Windows Management Instrumentation (WMI) will always wait at least one scanning interval until an error is shown. It is not possible to set a WMI sensor "down" immediately, so the first option will not apply to these sensor types (all other options can apply).

Note: If a sensor has defined error limits for channels, this sensor will always be set to a Down status immediately, so no "wait" option will apply.

Schedules, Dependencies, and Maintenance Window

Note: Inheritance for schedules, dependencies, and maintenance windows cannot be interrupted; the according settings from the parent objects will always be active. However, you can define additional settings here. They will be active in parallel to the parent objects' settings.

Schedule

Select a schedule from the list. Schedules can be used to monitor for a certain time span (days, hours) throughout the week. With the period list option it is also possible to pause monitoring for a specific time span. You can create new schedules and edit existing ones in the account settings. Note: Schedules are generally inherited. New schedules will be added to existing ones, so all schedules are active.

Maintenance Window

Specify if you want to set-up a one-time maintenance window. During a maintenance window this object and all child objects will not be monitored. They will enter a paused state then. Choose between:

  • Not set (monitor continuously): No maintenance window will be set.
  • Set up a one-time maintenance window: Pause monitoring within a maintenance window.

Maintenance Begins At

This field is only visible if maintenance window is enabled above. Use the date time picker to enter the start date and time of the maintenance window.

Maintenance End At

This field is only visible if maintenance window is enabled above. Use the date time picker to enter the end date and time of the maintenance window.

Dependency Type

Define a dependency type. Dependencies can be used to pause monitoring for an object depending on the status of another. You can choose between:

  • Use parent: Pause the current sensor if the device it is created on is in a Down status, or if it is paused by another dependency.
  • Select object: Pause the current sensor if the device it is created on is in an Down status, or if it is paused by another dependency. Additionally, pause the current sensor if a specific other object in the device tree is in a Down status, or if it is paused by another dependency. Select below.
  • Master object for parent: Make this sensor the master object for its parent device. The sensor will influence the behavior of the device it is created on: If the sensor is in a Down status, the device will be paused. For example, it is a good idea to make a Ping sensor the master object for its parent device to pause monitoring for all other sensors on the device in case the device cannot even be pinged. Additionally, the sensor will be paused if the parent group of its parent device is in a Down status, or if it is paused by another dependency.

Note: Testing your dependencies is easy! Simply choose Simulate Error Status from the context menu of an object that other objects depend on. A few seconds later all dependent objects should be paused. You can check all dependencies in your PRTG installation by selecting Devices | Dependencies from the main menu bar.

Dependency

This field is only visible if the select object option is enabled above. Click on the reading-glass symbol and use the object selector to choose an object on which the current sensor will be dependent on.

Delay (Seconds)

Define a time span. After the master object for this dependency comes back to an Up status, monitoring of the depending objects will be additionally delayed by the defined time span. This can help avoid false alarms, for example, after a server restart, by giving systems more time for all services to start up. Please enter an integer value in seconds. Note: This setting is not available if you choose this sensor to be the Master object for parent. In this case, please define delays in the parent Device Settings or the superior Group Settings.

Access Rights

User Group Access

Define which user group(s) will have access to the object you're editing. A table with user groups and right 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 settings of the parent object.
  • None: Users in this group cannot see or edit the object. The object does not show up in lists and 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.

For more details about access rights, please see section User Access Rights.

Channel Unit Configuration

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

Note: Custom channel types can be set on sensor level only.

More

My WMI sensors don't work. What can I do?

Edit Sensor Channels

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

Notifications

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

Others

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

Sensor Settings Overview

For information about sensor settings, please see the following sections:

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