Details

From https://www.ovirt.org/documentation/administration_guide/index.html:



Memory Ballooning


Virtual machines start with the full amount of virtual memory you have assigned to them. As virtual memory usage exceeds RAM, the host relies more on swap space. If enabled, memory ballooning lets virtual machines give up the unused portion of that memory. The freed memory can be reused by other processes and virtual machines on the host. The reduced memory footprint makes swapping less likely and improves performance.


Solution

To enable memory ballooning, click the Optimization tab in the New Cluster or Edit Cluster windows. Then select the Enable Memory Balloon Optimization checkbox. This setting enables memory overcommitment on virtual machines running on the hosts in this cluster. When this check box is selected, the MoM starts ballooning where and when possible, with a limitation of the guaranteed memory size of every virtual machine.


Supportive Information

The following resource is also helpful.

This security hardening control applies to the following category of controls within NIST 800-53: Configuration Management.This control applies to the following type of system RHEV.


References


Source