Hot-add and remove requirements for Windows Server 2016 Hyper-V

Q. What are the requirements for hot add and remove of memory in Windows Server 2016 Hyper-V?

A. Hot add and remove of memory, officially known as Runtime Memory Resize, is a new feature of Windows Server 2016 Hyper-V. While dynamic memory has been present since Windows Server 2012 the hot add/remove is different as dynamic memory monitors the memory used in a guest then adds/removes based on that usage. This dynamic changing of memory while very useful is not suitable for some scenarios, such as a hoster where constantly changing memory is challenging both for billing and resource planning. With hot add/remove a VM can have its memory resource changed to a specific value without requiring a restart of the guest OS. This would also be useful for many desktop scenarios.

The requirements to use hot add and remove are as follows:

Note that with the Runtime Memory Resize when memory is removed the actual memory seen in the VM will decrease which is different from dynamic memory pre-2016 that would leave the guest always seeing the high watermark of memory ever present in the VM (with the memory removed consumed by a kernel mode balloon device driver).