memory ballooning

Memory ballooning is a memory management technique in which the host is provided with unused memory space of its virtual machines( VM) and can use it for the guest virtual machines.

As soon as a virtual machine runs out of memory, the server requests unused memory from other virtual machines, thereby increasing its own memory capacity, which it makes available to the virtual machines.

Virtual machines can increase their free memory capacity by offloading infrequently used data, for example to virtual machine disks (VMDK), thus contributing to memory ballooning. Ballooning is used to determine which pages are available and can be used for memory expansion. The process of ballooning is characterized on the one hand by inflating the memory, the inflate, in which memory capacity is added, and on the other hand by shrinking the memory by making free memory available for the guest virtual machines.