<%NUMBERING1%>.<%NUMBERING2%>.<%NUMBERING3%> PRTG Manual: SNMP Linux Disk Free Sensor

The SNMP Linux Disk Free sensor monitors the free space on disks of a Linux/Unix system via the Simple Network Management Protocol (SNMP).

i_square_cyanThe free space that this sensor returns shows the disk space that is not yet used. Not all of this space may be available for use because a part of this space may be reserved by the system, for example, for redundancy purposes. For details, see the Knowledge Base: Why do SSH Disk Free and SNMP Linux Disk Free show different values for my target Linux system?

i_square_cyanFor a detailed list and descriptions of the channels that this sensor can show, see section Channel List.

SNMP Linux Disk Free Sensor

SNMP Linux Disk Free Sensor

Sensor in Other Languages

  • Dutch: SNMP Linux vrije schijf ruimte
  • French: Espace disque libre SNMP Linux
  • German: SNMP Linux-Datenträgerspeicher
  • Japanese: SNMP Linux ディスクの空き容量
  • Portuguese: Disco livre Linux SNMP
  • Russian: Свободное пространство диска в Linux по SNMP
  • Simplified Chinese: SNMP Linux 磁盘可用空间
  • Spanish: SNMP disco libre Linux

Remarks

  • This sensor supports the IPv6 protocol.
  • This sensor has a low performance impact.

Add Sensor

The Add Sensor dialog appears when you manually add a new sensor to a device. It only shows the settings that are required to create the sensor. Therefore, you do not see all settings in this dialog. You can change nearly all settings on the sensor's Settings tab after creation.

Basic Sensor Settings

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

Basic Sensor Settings

Basic Sensor 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.

i_round_blueIf the name contains angle brackets (<>), PRTG replaces them with braces ({}) for security reasons. For more information, see the Knowledge Base: What security features does PRTG include?

Parent Tags

Shows tags that the sensor inherits from its parent device, parent group, and parent probe.

i_round_blueThis setting is for your information only. You cannot change it.

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.

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

i_round_blueFor performance reasons, it can take some minutes until you can filter for new tags that you added.

The sensor has the following default tags that are automatically predefined in the sensor's settings when you add the sensor:

  • snmpdiskfreesensor
  • diskspacesensor

Priority

Select a priority for the sensor. This setting determines the position of the sensor in lists. The highest priority is at the top of a list. Choose from the lowest priority (i_priority_1) to the highest priority (i_priority_5).

i_round_blueUsually, a sensor connects to the IP Address or DNS Name of the parent device. See the device settings for details. For some sensors, you can explicitly define the monitoring target in the sensor settings.

Set Limits Checked for ALL Disks

In this section, you can set limits that are valid for all channels and all drives. With limits, you can define when the sensor shows the Warning or Down status, depending on the data provided by all drives that this sensor monitors. If you want to individually define limits for separate channels, use the limit settings in the channel settings.

i_round_redAll limits that you define here are valid in addition to the limits in the particular Channel settings. The limits are valid simultaneously, so the first limit that is breached applies.

Set Limits Checked For ALL Disks

Set Limits Checked For ALL Disks

Setting

Description

Percentage Limit Check

Enable or disable a limit check for the free space in percentage channels of all drives. By default, the sensor enables percentage limits with a lower warning limit and a 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 the 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 sensor limits that are valid for all percentage channels. Additional fields appear below. The sensor shows the Warning or the Down status when free space limits are above or below the limits.

Upper Error Limit

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

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

Upper Warning Limit

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

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

Lower Warning Limit

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

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

Lower Error Limit

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

i_round_redThe limits that you set here are valid for all channels of this sensor. You can additionally set individual limits for each channel in the channel settings. Both the limits that you 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 byte size channels. Additional fields appear below. The sensor shows the Warning or Down status when free space limits are above or below the value.

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

Upper Error Limit

This setting is only visible if you select 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 value, the sensor changes to the Down status. Enter an integer value or leave the field empty.

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

Upper Warning Limit

This setting is only visible if you select 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 value, the sensor changes to the Warning status. Enter an integer value or leave the field empty.

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

Lower Warning Limit

This setting is only visible if you select 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 value, the sensor changes to the Warning status. Enter an integer value or leave the field empty.

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

Lower Error Limit

This setting is only visible if you select 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 value, the sensor changes to the Down status. Enter an integer value or leave the field empty.

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

Alarm on Missing/Removed Disk

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

  • Deactivate alarm (default): Do not send an alert for a removed disk.
  • Activate alarm: Send an alert if a monitored disk is removed or not found.

Sensor Display

Sensor Display

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.

i_round_blueYou can set a different primary channel later by clicking b_channel_primary below a channel gauge 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.
    i_round_redYou cannot use this option in combination with manual Vertical Axis Scaling (available in the channel settings).

Stack Unit

This setting 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. We recommend that you change them centrally in the root group settings if necessary. To change a setting for this object only, click b_inherited_enabled under the corresponding setting name to disable the inheritance and to display its options.

i_square_cyanFor more information, see section Inheritance of Settings.

Scanning Interval

Click b_inherited_enabled to interrupt the inheritance.

Scanning Interval

Scanning Interval

Setting

Description

Scanning Interval

Select a scanning interval from the dropdown list. The scanning interval determines the amount of time that the sensor waits between two scans. Choose from:

  • 30 seconds
  • 60 seconds
  • 5 minutes
  • 10 minutes
  • 15 minutes
  • 30 minutes
  • 1 hour
  • 4 hours
  • 6 hours
  • 12 hours
  • 24 hours

i_round_blueYou can change the available intervals in the system administration on PRTG on premises installations.

If a Sensor Query Fails

Select the number of scanning intervals that the sensor has time to reach and to check a device again if a sensor query fails. Depending on the option that you select, the sensor can try to reach and to check a device again several times before the sensor shows the 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 the Warning status. Choose from:

  • Set sensor to down immediately: Set the sensor to the Down status immediately after the first request fails.
  • Set sensor to warning for 1 interval, then set to down (recommended): Set the sensor to the Warning status after the first request fails. If the second request also fails, the sensor shows the Down status.
  • Set sensor to warning for 2 intervals, then set to down: Set the sensor to the Down status only after the third request fails.
  • Set sensor to warning for 3 intervals, then set to down: Set the sensor to the Down status only after the fourth request fails.
  • Set sensor to warning for 4 intervals, then set to down: Set the sensor to the Down status only after the fifth request fails.
  • Set sensor to warning for 5 intervals, then set to down: Set the sensor to the Down status only after the sixth request fails.

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

i_round_blueIf you define error limits for a sensor's channels, the sensor immediately shows the Down status. None of the interval options apply.

i_round_blueIf a channel uses lookup values, the sensor immediately shows the Down status. None of the interval options apply.

Schedules, Dependencies, and Maintenance Windows

i_round_blueYou cannot interrupt the inheritance for schedules, dependencies, and maintenance windows. The corresponding settings from the parent objects are always active. However, you can define additional schedules, dependencies, and maintenance windows. They are active at the same time as the parent objects' settings.

Schedules, Dependencies, and Maintenance Windows

Schedules, Dependencies, and Maintenance Windows

Setting

Description

Schedule

Select a schedule from the list. You can use schedules to monitor during a certain time span (days or hours) every week. Choose from:

  • None
  • Saturdays
  • Sundays
  • Weekdays
  • Weekdays Eight-To-Eight (08:00 - 20:00)
  • Weekdays Nights (17:00 - 09:00)
  • Weekdays Nights (20:00 - 08:00)
  • Weekdays Nine-To-Five (09:00 - 17:00)
  • Weekends

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

Maintenance Window

Select if you want to set up a one-time maintenance window. During a maintenance window, monitoring stops for the selected object and all child objects. They show the Paused status instead. Choose between:

  • Do not set up a one-time maintenance window: Do not set up a one-time maintenance window. Monitoring is always active.
  • Set up a one-time maintenance window: Set up a one-time maintenance window and pause monitoring. You can define a time span for the pause below.

i_round_blueTo 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 setting 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 one-time maintenance window.

Maintenance Ends

This setting 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 one-time maintenance window.

Dependency Type

Select 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 the Down status or in the Paused status because of 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 the 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.

i_round_blueTo 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 setting is only visible if you enable Select a sensor above. Click b_search_light and use the object selector to select a sensor on which the current object will depend.

Dependency Delay (Sec.)

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

After the master sensor for this dependency returns to the Up status, PRTG additionally delays the monitoring of the dependent objects by the time span you define. This can prevent false alarms, for example, after a server restart or to give systems more time for all services to start. Enter an integer value.

i_round_redThis 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.

Access Rights

Click b_inherited_enabled to interrupt the inheritance.

Access Rights

Access Rights

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.

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

Channel Unit Configuration

Click b_inherited_enabled to interrupt the inheritance.

i_round_blueWhich channel units are available depends on the sensor type and the available parameters. If no configurable channels are available, this field shows No configurable channels.

Channel Unit Configuration

Channel Unit Configuration

Setting

Description

Channel Unit Types

For each type of channel, select the unit in which PRTG displays the data. If you define this setting on probe, group, or device level, you can inherit these settings to all sensors underneath. You can set units for the following channel types (if available):

  • Bandwidth
  • Memory
  • Disk
  • File
  • Custom

i_round_blueCustom channel types are only available on sensor level.

Channel List

i_round_blueWhich channels the sensor actually shows might depend on the monitored device, the available components, and the sensor setup.

Channel

Description

Downtime

In the channel table on the Overview tab, this channel never shows any values. PRTG uses this channel in graphs and reports to show the amount of time in which the sensor was in the Down status in percent.

Free Bytes [Partition]

The free space in bytes

Free INodes [Partition]

The free index nodes in percent

Free Space [Partition]

The free space in percent

Total

The free total disk space in bytes

More

i_square_blueKNOWLEDGE BASE

Why do SSH Disk Free and SNMP Linux Disk Free show different values for my target Linux system?

Monitoring Linux problem - SNMP port not reachable

What security features does PRTG include?

What SNMP sensors does PRTG offer?

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

Sensor Settings Overview

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