By default, virtual machines don’t support Hot Add (add RAM) and Hot Plug (add vCPU). You need to enable this capability on a per-VM basis in order to use it. To do so, you must first shut down the virtual machine since you can’t modify these settings while it’s running. Then, open the virtual machine’s properties, navigate to the Options tab and choose the Memory/CPU Hotplug option in the Advanced section. At the right-hand side of the window, note that there are two section – one for memory and one for CPU. Choose the options you like and then click OK. After this setting is changed, you can restart the VM.
Now, when you look at the VM details, notice that you’re provided with the maximum hot-add memory for the VM. In this case, that’s 64 GB.
When I look at the system properties for the VM, here’s what I see: 4 GB of RAM and 2 processors.
While the VM is running, I’m going to increase this to 6 GB of RAM and 3 processors.
Without a reboot, here is what I now see in the system properties.
And he’s a look at the Task Manager showing 3 CPUs and 6 GB of RAM
If you’ve successfully hot added RAM or CPU to a running virtual machine, respond to this posting (or, leave a response to my forum posting) with your operating system, edition (standard, enterprise, etc), service pack level/kernel version, and architecture (32/64-bit). If enough people respond, I’ll compile all of the results into a usable format and republish it.