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What can I check in the case of high memory usage?



The memory utilization on several servers with PRTG probes (local and remote probes) is getting too high. As the memory and system health sensors in my PRTG installation show, RAM is consumed to a minimum which results in sensor errors.

What can I do to find the reason for this high memory usage? Which system parameters should I investigate?

memory memory-leaks prtg ram

Created on Nov 13, 2014 4:29:21 PM by  Gerald Schoch [Paessler Support]

3 Replies

Accepted Answer



This article applies to PRTG Network Monitor 14 or later

Reasons for High Memory Usage on PRTG Servers

There can be various reasons for high memory consumption on servers where PRTG probes are running. Most likely, this comes from over-utilization of PRTG, the general system setup, or interfering Windows programs. Usually, PRTG does not leak memory but in some rare cases there might be system internal issues causing high memory consumption by PRTG itself. If none of the points below apply to your setup, please contact our support via the support bundle.

This article sums up various parameters you should check if you encounter high memory values:

  • Check the PRTG system requirements. Minimum requirement for RAM memory is 1024 MB for a common usage scenario of PRTG. The bigger your installation, the more RAM you should provide. Also remember that 64bit systems need more memory than 32bit systems!
  • Sensor related:
  • Toplist related:
    • Your PRTG installation contains too many toplists.
    • Toplists with very heterogeneous traffic and long intervals consume a lot of RAM. Minimize the covered time period in the settings of a toplist.
    • Toplists with too many entries per toplist need a lot of memory. Decrease the Top Count in the settings of a toplist.
  • Overall system related:
    • Too many users which are active at the same time on one PRTG server can cause many sessions and states which then again lead to increasing memory usage.
    • Probes that try to re-connect very often cause high memory usage. Ensure a stable network connection for your remote probes!
    • Check the system(s) on which a PRTG probe is running for interfering Windows programs and services, for example, via the task manager.
    • If necessary, stop service(s) with heavy load and clear the cache on the system running your PRTG probe.
    • Always run the latest PRTG version! Outdated PRTG versions might contain unsolved issues. These can result in an unnecessary high number of CPU threads which then again round off RAM.
    • Check the memory consumption on your PRTG core server system: Choose Setup | PRTG Status from the main menu in the PRTG web interface and navigate to section Core System Memory where PRTG tracks all important memory areas. There you might find potential reasons for memory leaks.
    • Check also your Core Health and Probe Health sensors to find out which system values increase.

Created on Nov 13, 2014 4:31:05 PM by  Gerald Schoch [Paessler Support]

Last change on Nov 17, 2014 12:07:14 PM by  Gerald Schoch [Paessler Support]



We saw in a test environment that a remote probe with 1500 sensors ran out of memory after a week. It suddenly starts on Friday with the following log entries:

Connect from to XXX.XXX.XXX.XXX:23560 Client Connection: Out of memory Try to Create new Connection Exception in Scheduler: Out of memory (State=11) Create new Connection

When I had a look today I saw that the memory of the remote probe increased to 2.8 GB RAM usage. Now about an hour after the restart it is around 150 MB which seems to be more OK.

Created on Oct 19, 2015 9:56:12 AM



Hi Adestis,

I'd like to have a look into the log files of your installation to see what's causing the issue. Can you please forward a support bundle by clicking on the "Setup > Contact Support" button in the web GUI? Please refer to this knowledge base article. Thank you!

Best regards, Felix

Created on Oct 19, 2015 10:42:13 AM by  Felix Saure [Paessler Support]

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.