Virtual Machine vCPU and vNUMA Rightsizing – Rules of Thumb
Using virtualization, we have all enjoyed the flexibility to quickly create virtual machines with various virtual CPU (vCPU) configurations for a diverse set of workloads. But as we virtualize larger and more demanding workloads, like databases, on top of the latest generations of processors with up to 24 cores, special care must be taken in vCPU and vNUMA configuration to ensure performance is optimized.
Btw. you´ll be thrilled by our upcoming NUMA dashboard integrations that are available by end of this week.
Much has been said and written about how to optimally configure the vCPU presentation within a virtual machine – Sockets x Cores per Socket
Side bar: When you create a new virtual machine, the number of vCPUs assigned is divided by the Cores per Socket value (default = 1 unless you change the dropdown), to give you the calculated number of Sockets. If you are using PowerCLI, these properties are known as NumCPUs and NumCoresPerSocket. In the example screenshot above, 20 vCPUs (NumCPUs) divided by 10 Cores per Socket (NumCoresPerSocket) results in 2 Sockets. Let’s refer to this virtual configuration as 2 Sockets x 10 Cores per Socket.
HistoryThe ability to set this presentation was originally introduced in vSphere 4.1 to overcome operating system license limitations. As of vSphere 5, those configuration items now set the virtual NUMA (vNUMA) topology that is exposed to the guest operating system.
NUMA is becoming increasingly more important to ensure workloads, like databases, allocate and consume memory within the same physical NUMA node that the vCPUs are scheduled. When a virtual machine is sized larger than a single physical NUMA node, a vNUMA topology is created and presented to the guest operating system. This virtual construct allows a workload within the virtual machine to benefit from physical NUMA, while continuing to support functions like vMotion.
Read the entire article here, Virtual Machine vCPU and vNUMA Rightsizing – Rules of Thumb
Via the fine folks at opvizor.