This diagnostic alert warns you when your operating system's free memory falls below a set threshold on your Confluence server, or individual Confluence node.  The threshold is calculated as a percentage. 

The following appears in the application log:

WARNING ; OS ; OS-1001 ; Low free memory ; not-detected ;  ;  ; {"freeInMegabytes":...,"totalInMegabytes":...,"minimumInMegabytes":...}

This alert is enabled by default in Confluence 6.11 or later. 

To resolve this issue

To resolve this issue you'll need to either provision more memory, or free up memory by moving non-essential applications or utilities to another server.

What will happen if I ignore this alert? 

Your site may be more susceptible to out of memory errors, which can lead to Confluence crashing when Confluence is performing memory intensive tasks.

Can I change the threshold? 

Yes, you can change the threshold of this alert using the following system property:

diagnostics.os.min.free.memory.megabytes

See Configuring System Properties for more information on setting system properties.