Sorry for my English ....
On Linux distributions, Portal for ArcGIS runs from a Java Virtual Machine (JVM) instance. The default out-of-the-box configuration allocates 2GB of available RAM on your server to this JVM.
I looked in this post (https://community.esri.com/t5/arcgis-geoevent-server-blog/increase-the-ram-allocation-to-the-jvm-run...) for the possibility of changing the size of the JVM in ArcGIS Geoevent.
Is it possible to make this same change in Portal for ArcGIS JVM?
Here are my current Linux JVM configuration processes
