PRTG Manual: WMI Free Disk Space (Multi Drive) Sensor

The WMI Free Disk Space (Multi Drive) sensor monitors the free disk space of one or multiple drive(s) using Windows Management Instrumentation (WMI). It shows the space in percent and total. One single sensor is used for all drives; the data is presented in different channels.

Note: This sensor is also supported on Windows XP and earlier.

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.

The following settings for this sensor differ in the 'Add Sensor' dialog in comparison to the sensor's settings page:

WMI Volume Specific

Drive

From the drop down menu select the drive(s) you want to monitor. We recommend using the default value. You can choose All to monitor all available drives or you can choose one specific drive letter to monitor this single drive only. The data in the drop down menu may also contain drive letters that do not exist on your device. The drive setting cannot be changed once the sensor is created.

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 Disk Free Configuration

Drive

Shows the drive(s) that this sensor is monitoring; either All or a specific drive letter. Once a sensor is created this value cannot be changed. It is shown for reference purposes only. If you need to change this, please add the sensor anew.

Set limits checked against ALL disks

In this section you can set limits that are valid for all channels and all drives. By entering limits, you can define when the sensor will enter a Warning or Down status; depending on the data provided by all drives that this sensor monitors. If you want to define limits for separate channels individually please use the limit settings in the sensor's Channels tab. Note: All limits defined here are valid additionally to the limits defined in the Channels tab!

Percentage Limit Check

Enable or disable a limit check for the free space in percentage channels of all drives. By default percentage limits are enabled with lower warning and lower error limit. Choose between:

  • Disable Percentage Limits: Do not use the drives' data to control the sensor's status.
  • Enable Percentage Limits: Define limits. Additional fields appear below. The sensor will enter a warning or down state when free space limits are undercut or overrun.

Upper Error Limit

This field is only visible if percentage limit check is enabled above. Specify an upper limit in percent for a Down status. If the free disk space of one of your drives overruns this percent value, the sensor will be set to Down. Please enter an integer value or leave the field empty. Note: The limits set here are valid for all channels of this sensor. You can additionally set individual limits for each sensor channel in the Sensor Channels Settings. The limits set here and in the channel settings are valid simultaneously!

Upper Warning Limit

This field is only visible if percentage limit check is enabled above. Specify an upper limit in percent for a Warning status. If the free disk space of one of your drives overruns this percent value, the sensor will be set to Warning. Please enter an integer value or leave the field empty. Note: The limits set here are valid for all channels of this sensor. You can additionally set individual limits for each sensor channel in the Sensor Channels Settings. The limits set here and in the channel settings are valid simultaneously!

Lower Warning Limit

This field is only visible if percentage limit check is enabled above. Specify a lower limit in percent for a warning state. If the free disk space of one of your drives undercuts this percent value, the sensor will be set to warning. Please enter an integer value or leave the field empty. Note: The limits set here are valid for all channels of this sensor. You can additionally set individual limits for each sensor channel in the Sensor Channels Settings. The limits set here and in the channel settings are valid simultaneously!

Lower Error Limit

This field is only visible if percentage limit check is enabled above. Specify a lower limit in percent for entering a Down status. If the free disk space of one of your drives undercuts this percent value, the sensor will be set to Down. Please enter an integer value or leave the field empty. Note: The limits set here are valid for all channels of this sensor. You can additionally set individual limits for each sensor channel in the Sensor Channels Settings. The limits set here and in the channel settings are valid simultaneously!

Byte Limit Check

Enable or disable a limit check for the free bytes channels of all drives. Choose between:

  • Disable Byte Limits: Do not use the drives' data to control the sensor's status.
  • Enable Byte Limits: Define limits. Additional fields appear below. The sensor will enter a warning or down state when free space limits are undercut or overrun.

Upper Error Limit

This field is only visible if byte limit check is enabled above. Specify an upper limit. Use the same unit as shown by the free bytes channels of this sensor (by default this is MByte). If the free disk space of one of your drives overruns this bytes value, the sensor will be set to Down. Please enter an integer value or leave the field empty. Note: The limits set here are valid for all channels of this sensor. You can additionally set individual limits for each sensor channel in the Sensor Channels Settings. The limits set here and in the channel settings are valid simultaneously!

Upper Warning Limit

This field is only visible if byte limit check is enabled above. Specify an upper limit. Use the same unit as shown by the free bytes channels of this sensor (by default this is MByte). If the free disk space of one of your drives overruns this bytes value, the sensor will be set to Warning. Please enter an integer value or leave the field empty. Note: The limits set here are valid for all channels of this sensor. You can additionally set individual limits for each sensor channel in the Sensor Channels Settings. The limits set here and in the channel settings are valid simultaneously!

Lower Warning Limit

This field is only visible if byte limit check is enabled above. Specify a lower limit. Use the same unit as shown by the free bytes channels of this sensor (by default this is MByte). If the free disk space of one of your drives undercuts this bytes value, the sensor will be set to Warning. Please enter an integer value or leave the field empty. Note: The limits set here are valid for all channels of this sensor. You can additionally set individual limits for each sensor channel in the Sensor Channels Settings. The limits set here and in the channel settings are valid simultaneously!

Lower Error Limit

This field is only visible if byte limit check is enabled above. Specify a lower limit. Use the same unit as shown by the free bytes channels of this sensor (by default this is MByte). If the free disk space of one of your drives undercuts this bytes value, the sensor will be set to Down. Please enter an integer value or leave the field empty. Note: The limits set here are valid for all channels of this sensor. You can additionally set individual limits for each sensor channel in the Sensor Channels Settings. The limits set here and in the channel settings are valid simultaneously!

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.

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.

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 pause monitoring for a certain time span (days, hours) throughout the week. 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.

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.

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.

Channels

Click on the Channels tab to change display settings, spike filter, and limits. 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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