vSphere 5.0 introduces support for exposing virtual NUMA topology to guest operating systems, which can improve performance by facilitating guest operating system and application NUMA optimizations.

Virtual NUMA topology is available to hardware version 8 virtual machines and is enabled by default when the number of virtual CPUs is greater than eight. You can also manually influence virtual NUMA topology using advanced configuration options.

You can affect the virtual NUMA topology with two settings in the vSphere Client: number of virtual sockets and number of cores per socket for a virtual machine. If the number of cores per socket (cpuid.coresPerSocket) is greater than one, and the number of virtual cores in the virtual machine is greater than 8, the virtual NUMA node size matches the virtual socket size. If the number of cores per socket is less than or equal to one, virtual NUMA nodes are created to match the topology of the first physical host where the virtual machine is powered on.

When the number of virtual CPUs and the amount of memory used grow proportionately, you can use the default values. For virtual machines that consume a disproportionally large amount of memory, you can override the default values in one of the following ways:

Increase the number of virtual CPUs, even if this number of virtual CPUs is not used. See Change the Number of Virtual CPUs.

Use advanced options to control virtual NUMA topology and its mapping over physical NUMA topology. See Virtual NUMA Controls.