PRTG Manual: SSH Disk Free Sensor

Credentials

This sensor requires credentials for Linux/Solaris/macOS (SSH/WBEM) systems in the settings of the parent device.

Distributions

This sensor does not support all Linux/Unix and macOS distributions.

Performance impact

This sensor has a medium performance impact.

IPv4

This sensor only supports IPv4.

Add Sensor dialog

You can select up to 100 disks in the Add Sensor dialog. If you select more disks, you cannot create the sensor. Add the sensor multiple times to monitor more than 100 disks with several sensors.

Knowledge Base

• Knowledge Base: Which encryption algorithms do PRTG SSH sensors support?
• Knowledge Base: SSH and SFTP sensors in Unknown status

Connection Timeout (Sec.)

Define a timeout in seconds for the connection. This is the time that the sensor waits to establish a connection to the host. Keep this value as low as possible. Enter an integer. The maximum timeout value is 900 seconds (15 minutes).

Make sure that the connection timeout is a value that is higher than the shell timeout to avoid potential errors.

Shell Timeout (Sec.)

Define a timeout in seconds for the shell response. This is the time in seconds the sensor waits for the shell to return a response after it has sent its specific command (for example, cat /proc/loadavg). The maximum value is 300 seconds (5 minutes). Enter an integer.

Make sure that the shell timeout is a value that is lower than the connection timeout to avoid potential errors.

SSH Port Inheritance

Define which port this sensor uses for the SSH connection:

• Inherit port from parent device (default): Use the port number as defined in the Credentials for Linux/Solaris/macOS (SSH/WBEM) Systems section of the parent device settings.
• Do not inherit port (enter a custom SSH port): Define a custom port number below and do not use the port number from the parent device settings.

Custom SSH Port

This setting is only visible if you select Do not inherit port (enter a custom SSH port) above.

Enter the port number (between 1 and 65535) that this sensor uses for the SSH connection. Enter an integer.

SSH Engine

Select the SSH engine that you want to use to access data with this SSH sensor:

• Inherit from parent device (default): Use the SSH engine that you defined in the parent device settings or higher up in the object hierarchy. If you have not changed the SSH engine, this is the recommended option.
• Default: This is the default SSH engine. It provides the best performance and security. It is set by default in objects that are higher up in the hierarchy, so usually you can keep the Inherit from parent device (default) option.
• Compatibility mode (deprecated): Use this only if the default SSH engine does not work on a target device. The compatibility mode is the SSH engine that PRTG used in previous versions. It is deprecated. We will remove this legacy mode soon, so try to get your SSH sensors to run with the default SSH engine.

We strongly recommend that you use the default SSH engine.

The option you select here overrides the selection of the SSH engine in a higher object: a parent device, group, probe, or root.

Result Handling

Define what PRTG does with the sensor result:

• Discard result (default): Do not store the sensor result.
• Store result: Store the sensor result and the last response in the \Logs\sensors subfolder of the PRTG data directory on the probe system. The file names are Result of Sensor [ID].txt, Result of Sensor [ID].Data.txt, and Result of Sensor [ID] (SSHv2).txt. This setting is for debugging purposes. PRTG overwrites these files with each scanning interval.
• Store result in case of error: Store the last sensor result only if the sensor shows the Down status.

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

In a cluster, PRTG stores the result in the PRTG data directory of the master node.

Percentage Limit Check

By default, the sensor enables percentage limits with a lower warning limit and a lower error limit. Enable or disable a limit check for the free space in percentage channels of all drives:

• 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 (default): 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 (default) 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 or leave the field empty.

The 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 (default) 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 or leave the field empty.

The 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 (default) 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 or leave the field empty.

The 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 (default) 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 or leave the field empty.

The 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 (default): 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.

By 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 (the default unit 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 or leave the field empty.

The 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 (the default unit 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 or leave the field empty.

The 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 (the default unit 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 or leave the field empty.

The 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 (the default unit 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 or leave the field empty.

The 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.

Primary Channel

Select a channel from the list to define it as the primary channel. In the device tree, PRTG displays the last value of the primary channel 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 below a channel gauge on the sensor's Overview tab.

Graph Type

Define how this sensor shows different channels:

• 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.
  You 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 select Stack channels on top of each other above.

Select a unit from the list. PRTG stacks all channels with this unit 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.

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.

Free Bytes [Mounted Partition]

The free space

Free Space [Mounted Partition]

The free space (%)

Total

The total space