The CPU hot plug option lets you add CPU resources for a virtual machine while the machine is turned on.

The following conditions apply:

For best results, use virtual machines that are compatible with ESXi 5.0 and later.

Hot-adding multicore virtual CPUs is supported only with virtual machine that are compatible with ESXi 5.0 and later.

Not all guest operating systems support CPU hot add. You can disable these settings if the guest is not supported.

To use the CPU hot-add feature with virtual machines that are compatible with ESXi 4.x and later, set the Number of cores per socket to 1.

Adding CPU resources to a running virtual machine with CPU hot plug enabled disconnects and reconnects all USB passthrough devices connected to that virtual machine.

Verify that the virtual machine is running under the following conditions:

VMware Tools is installed. This condition is required for hot plug functionality with Linux guest operating systems.

The virtual machine has a guest operating system that supports CPU hot plug.

The virtual machine compatibility is ESX/ESXi 4.x or later.

The virtual machine is turned off.

Required privileges: Virtual Machine.Configuration.Settings


Right-click the virtual machine and select Edit Settings.


To locate a virtual machine, select a datacenter, folder, cluster, resource pool, host, or vApp.


Click the Related Objects tab and click Virtual Machines.


On the Virtual Hardware tab, expand CPU, and select Enable CPU Hot Add.


Click OK.

You can now add CPUs while the virtual machine is turned on.