When selecting "Enable CPU Hot Add" in the virtual machines Edit Settings dialogue (vmx option: "vcpu.hotadd = true"), vNUMA is disabled for the VM. As a result, even if the virtual machine is created with more vCPUs than cores in one of the underlying hardware's NUMA node (or threads if "numa.vcpu.preferHT = true" is set), only one virtual node (VPD) will be presented to the VM and the memory interleaved over the multiple resulting NUMA clients (PPDs).


You might see the following in the vmware.log on ESXi 6.7 and later:

<datetime> vmx| I125: numa: Hot add is enabled and vNUMA hot add is disabled, forcing UMA.

Alternatively in ESXi 6.5 and earlier:

<datetime> vmx| W110: NUMA and VCPU hot add are incompatible. Forcing UMA.

VMware vSphere ESXi 6.5
VMware vSphere ESXi 7.0.x
VMware vSphere ESXi 6.0
VMware vSphere ESXi 6.7

None. If you do not plan to use vCPU hotplug, do not enable it. Add the maximum vCPUs that might be needed by the workload. In rare cases, where vCPU hot plug is required, try to limit the maximum number of vCPUs to stay below the physical NUMA node core count so that the virtual machine can be scheduled in a single NUMA node.

Login to vCenter UI

Power off the VM to edit the check box for Enable CPU Hot Add

Select the Virtual Machine (centos8) > Actions > Edit Settings > Virtual Hardware > expand CPU > CPU Hot Plug. 

Disable uncheck the box Enable CPU Hot Add
Enable check the box Enable CPU Hot Add 

Additional Information

For translated versions of this article, see:

• 日本語: VCPU ホットプラグが有効化されていると vNUMA が無効になる (2113498)

Using Virtual NUMA (VMware Docs)

Enabling vCPU HotAdd creates fake NUMA nodes on Windows (83980)