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My probe system is running out of disk space. What can I do?



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The Probe Health sensor warns me that the free data storage is below the warning limit. The sensor message is The probe system is running out of disk space. Please add additional space to the PRTG data path.

What can I do if the available disk space on my probe system runs short?

data-storage disk-free diskspace probe probe-health prtg

Created on May 21, 2015 1:17:30 PM by  Gerald Schoch [Paessler Support]

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This article applies to PRTG Network Monitor 14 or later

Low Disk Space on Probe System

The Probe Health sensor monitors the status of a PRTG probe. Among other parameters, this sensor type shows also the free disk space on the probe system in the dedicated channel Data Storage Free.

As of version 18.x.37, PRTG dynamically sets limits for this channel. If the limits are undercut, the sensor will show the following message:

Data storage is less than %s.

For versions previous to 18.x.37, this channel will show a Warning status by default if there are less than 5120 Mbyte available on the disk, and a Down status for less than 1024 Mbyte. In this case, the sensor will show a message like the following:

2.394 MByte (Data Storage Free) is below the warning limit of 5.120 MByte. The probe system is running out of disk space. Please add additional space to the PRTG data path. For details, please see

Most sensor types write their data to the disk on the PRTG core server system—usually, you need about 200 kilobyte of disk space per sensor per day. There also some sensor types (for example, Syslog Receiver, SNMP Trap Receiver, HTTP Full Web Page) that write data to the disk on the (remote) probe system. These sensors can consume away available disk space on a probe machine if you do not configure them appropriately.

You can check the PRTG data path to see which data takes most space. Especially, consider the following points on the system running the probe where the Probe Health sensor shows a warning or error status:

  • Do you run SNMP Trap Receiver or Syslog Receiver sensors? Check the size of the corresponding database folder, Trap Database or Syslog Database. If you encounter very large disk usage here, consider to re-configure these sensors in PRTG so they store less data. For example, refine the include filters of these sensors.
  • Do you run a HTTP Full Web Page sensor?
    • Do you have a huge Screenshots (Fullpage Sensor) directory? Check the Full Page Download Settings of this sensor. If you have set the option to store screenshots of all sensor results in section Result Handling and have problems with too low disk space, please choose another option.
    • Also check the following cache folder on the probe system where using this sensor type can result in a huge amount of used disk space and clean it up if necessary: C:\Windows\System32\config\systemprofile\AppData\Local\Microsoft\Windows\Temporary Internet Files\Content.IE5
  • Have you set appropriate data purging limits? For the HTTP Full Page sensor, you can set these limits in the Core & Probes settings in PRTG web interface, the Syslog and Trap Receiver sensors have a data purging option in their sensor settings. The data purging option enables you to automatically delete old data to free disk space. Of course, you can clean up PRTG’s data path manually, but be careful that you do not delete current monitoring data or data that you still need to analyze.

If the default limits of the Probe Health sensor for the available disk space are too high for your purposes (for example, because you do not use Syslog or Trap sensors), you can change these limits manually so that you do not get a warning or error message too soon. Open the settings of the Data Storage Free channel and enter lower limits that are more convenient for your monitoring scenario into the according Lower Warning Limit and Lower Error Limit fields. For details, please see PRTG Manual: Sensor Channels Settings

Created on May 21, 2015 5:20:32 PM by  Gerald Schoch [Paessler Support]

Last change on Feb 2, 2018 12:45:27 PM by  Brandy Mauff [Paessler Support]

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Disclaimer: The information in the Paessler Knowledge Base comes without warranty of any kind. Use at your own risk. Before applying any instructions please exercise proper system administrator housekeeping. You must make sure that a proper backup of all your data is available.