6.0

Using NUMA Systems with ESXi
ESXi supports memory access optimization for Intel and AMD Opteron processors in server architectures
that support NUMA (non-uniform memory access).
After you understand how ESXi NUMA scheduling is performed and how the VMware NUMA algorithms
work, you can specify NUMA controls to optimize the performance of your virtual machines.
Change the Number of Virtual CPUs
You can configure a virtual machine that runs on an ESXi host to have up to 64 virtual CPUs.
IMPORTANT When you configure your virtual machine for multicore virtual CPU settings, you must ensure
that your configuration complies with the requirements of the guest operating system EULA.
Prerequisites
Launch the vSphere Client and log in to a vCenter Server system.
Procedure
1 In the vSphere Client, right-click the virtual machine in the inventory and select Edit Settings.
2 Click the Hardware tab and select CPUs.
3 Select a value from the Number of virtual sockets drop-down menu.
4 Select a value from the Number of cores per socket drop-down menu.
The resulting total number of cores is a number equal to or less than the number of logical CPUs on the
host.
5 Click OK.
Associate Virtual Machines with Specific Processors
You might be able to improve the performance of the applications on a virtual machine by pinning its
virtual CPUs to fixed processors. This allows you to prevent the virtual CPUs from migrating across NUMA
nodes.
Prerequisites
Launch the vSphere Client and log in to a vCenter Server system.
Procedure
1 In the vSphere Client, right-click the virtual machine in the inventory and select Edit Settings.
2 Select the Resources tab, and select Advanced CPU.
3 In the Scheduling Affinity panel, set the CPU affinity to the preferred processors.
NOTE You must manually select the boxes for all processors in the NUMA node. CPU affinity is
specified on a per-processor, not on a per-node, basis.
Chapter 25 Resource Management for Single Hosts
VMware, Inc. 379