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

Drive

Select the drives that you want to monitor from the dropdown list. We recommend that you use the default value.

You can select All to monitor all available drives, or you can select one specific drive letter to monitor a single drive only. The dropdown list might also contain drive letters that do not exist on your device.

You cannot change the drive setting after creating the sensor.

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.

It 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).

Drive

Shows the drives that this sensor monitors. This is either All or a specific drive letter. Once you have created the sensor, you cannot change this value. It is shown for reference purposes only. If you need to change this value, add the sensor anew.

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:

• Only use the limits in the settings of the percentage channels: Do not define sensor limits that are valid for all percentage channels. The sensor only uses limits that you define in the settings of the particular "free space in percent" channels to determine the status.
• Use the limits of both the sensor and the channel settings: Define limits for the sensor that are valid for all drives (percentage channels). Additional fields appear below. The sensor shows a Warning or Down status when free space limits fall below the defined value or are exceeded.

Upper Error Limit

This field is only visible if you enable Use the limits of both the sensor and the channel settings above. Specify an upper limit in percent for a Down status. If the free disk space of one of your drives exceeds this percent value, the sensor changes to a Down status. Enter an integer value or leave the field empty.

The limits set here are valid for all channels of this sensor. You can additionally set individual limits for each channel in the channel settings. The limits set here and in the channel settings are valid simultaneously.

Upper Warning Limit

This field is only visible if you enable Use the limits of both the sensor and the channel settings above. Specify an upper limit in percent for a Warning status. If the free disk space of one of your drives exceeds this percent value, the sensor changes to a Warning status. Enter an integer value or leave the field empty.

The limits set here are valid for all channels of this sensor. You can additionally set individual limits for each channel in the channel settings. The limits set here and in the channel settings are valid simultaneously.

Lower Warning Limit

This field is only visible if you enable Use the limits of both the sensor and the channel settings above. Specify a lower limit in percent for a Warning status. If the free disk space of one of your drives falls below this percent value, the sensor changes to a Warning status. Enter an integer value or leave the field empty.

The limits set here are valid for all channels of this sensor. You can additionally set individual limits for each channel in the channel settings. The limits set here and in the channel settings are valid simultaneously.

Lower Error Limit

This field is only visible if you enable Use the limits of both the sensor and the channel settings above. Specify a lower limit in percent for a Down status. If the free disk space of one of your drives falls below this percent value, the sensor changes to a Down status. Enter an integer value or leave the field empty.

The limits set here are valid for all channels of this sensor. You can additionally set individual limits for each channel in the channel settings. The limits set here and in the channel settings are valid simultaneously.

Size Limit Check

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

• Only use the limits in the settings of the byte size channels: Do not define sensor limits that are valid for all byte size channels. The sensor only uses limits that you define in the settings of the particular free space in bytes channels to determine the status.
• Use the limits of both the sensor and the channel settings: Define limits for the sensor that are valid for all drives (byte size channels). Additional fields appear below. The sensor shows a Warning or Down status when free space limits fall below the defined value or are exceeded.

By default, byte size limits are not enabled for drives.

Upper Error Limit

This field is only visible if you enable Use the limits of both the sensor and the channel settings above. Specify an upper limit. Use the same unit as shown by the free bytes channels of this sensor (by default this is MB). If the free disk space of one of your drives exceeds this bytes value, the sensor changes to a Down status. Enter an integer value or leave the field empty.

The limits set here are valid for all channels of this sensor. You can additionally set individual limits for each channel in the channel settings. The limits set here and in the channel settings are valid simultaneously.

Upper Warning Limit

This field is only visible if you enable Use the limits of both the sensor and the channel settings above. Specify an upper limit. Use the same unit as shown by the free bytes channels of this sensor (by default this is MB). If the free disk space of one of your drives exceeds this bytes value, the sensor changes to a Warning status. Enter an integer value or leave the field empty.

The limits set here are valid for all channels of this sensor. You can additionally set individual limits for each channel in the channel settings. The limits set here and in the channel settings are valid simultaneously.

Lower Warning Limit

This field is only visible if you enable Use the limits of both the sensor and the channel settings above. Specify a lower limit. Use the same unit as shown by the free bytes channels of this sensor (by default this is MB). If the free disk space of one of your drives falls below this bytes value, the sensor changes to a Warning status. Enter an integer value or leave the field empty.

The limits set here are valid for all channels of this sensor. You can additionally set individual limits for each channel in the channel settings. The limits set here and in the channel settings are valid simultaneously.

Lower Error Limit

This field is only visible if you enable Use the limits of both the sensor and the channel settings above. Specify a lower limit. Use the same unit as shown by the free bytes channels of this sensor (by default this is MB). If the free disk space of one of your drives falls below this bytes value, the sensor changes to a Down status. Enter an integer value or leave the field empty.

The limits set here are valid for all channels of this sensor. You can additionally set individual limits for each channel in the channel settings. The limits set here and in the channel settings are valid simultaneously.

Alarm on Missing/Removed Disk

If a monitored disk is removed or not found, values are set to zero. Select the alarm approach in this case:

• Deactivate alarm (default): Select this option if you do not want an alarm for a removed disk.
• Activate alarm: Select this option if you want to be alerted if a monitored disk is removed.

Sensor Result

Define what PRTG does with the sensor results:

• Discard sensor result: Do not store the sensor result.
• Write sensor result to disk (file name: Result of Sensor [ID].txt): Store the last result received from the sensor to the \Logs\sensors subfolder of the PRTG data directory on the probe system (master node, if in a cluster). File names: Result of Sensor [ID].txt and Result of Sensor [ID].Data.txt. This is for debugging purposes. PRTG overwrites these files with each scanning interval.

This option is not available when the sensor runs on the hosted probe of a PRTG hosted by Paessler instance.

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.

You 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.
  This 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.

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.

Sensors 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.

If you define error limits for a sensor's channels, the sensor immediately shows a Down status. No "wait" option applies.

If a channel uses lookup values, the sensor immediately shows a Down status. No "wait" options apply.

Schedule

Select a schedule from the list. Schedules can be used to monitor for a certain time span (days or hours) every week.

You can create schedules, edit schedules, or pause monitoring for a specific time span. For more information, see section Account Settings—Schedules.

Schedules are generally inherited. New schedules are added to schedules that you already set up, so all schedules are active at the same time.

Maintenance Window

Specify if you want to set up a one-time maintenance window. During a maintenance window, the selected object and all child objects are not monitored. They are in a Paused status instead. Choose between:

• Not set (monitor continuously): No maintenance window is set and monitoring is always active.
• Set up a one-time maintenance window: Pause monitoring within a maintenance window. You can define a time span for a monitoring pause below and change it even for an active maintenance window.

To terminate an active maintenance window before the defined end date, change the time entry in Maintenance Ends to a date in the past.

Maintenance Begins

This field is only visible if you enable Set up a one-time maintenance window above. Use the date time picker to enter the start date and time of the maintenance window.

Maintenance Ends

This field is only visible if you enable Set up a one-time maintenance window above. Use the date time picker to enter the end date and time of the maintenance window.

Dependency Type

Define a dependency type. You can use dependencies to pause monitoring for an object depending on the status of a different object. You can choose from:

• Use parent: Use the dependency type of the parent object.
• Select a sensor: Use the dependency type of the parent object. Additionally, pause the current object if a specific sensor is in a Down status or in a Paused status caused by another dependency.

• Master sensor for parent: Make this sensor the master object for its parent device. The sensor influences the behavior of its parent device: If the sensor is in a Down status, the device is 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 is paused if the parent group is paused by another dependency.

To test your dependencies, select Simulate Error Status from the context menu of an object that other objects depend on. A few seconds later, all dependent objects are paused. You can check all dependencies under Devices | Dependencies in the main menu bar.

Dependency

This field is only visible if you enable Select a sensor above. Click the Search button and use the object selector to select a sensor on which the current object will depend.

Dependency Delay (Sec.)

This field is only visible if you enable Select a sensor above. Define a time span in seconds for dependency delay.

After the master sensor for this dependency comes back to an Up status, monitoring of the dependent objects is additionally delayed by the defined time span. This can prevent false alarms, for example, after a server restart, by giving systems more time for all services to start up. Enter an integer value.

This setting is not available if you set this sensor to Use parent or to be the Master sensor for parent. In this case, define delays in the parent device settings or in its parent group settings.

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.

For more details on access rights, see section Access Rights Management.

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

Custom channel types can be set on sensor level only.