VMware vSphere – Why checking NUMA Configuration is so important!
Non-uniform memory access (NUMA) is a computer memory design used in multiprocessing, where the memory access time depends on the memory location relative to the processor. Under NUMA, a processor can access its own local memory faster than non-local memory (memory local to another processor or memory shared between processors). The benefits of NUMA are limited to particular workloads, notably on servers where the data is often associated strongly with certain tasks or users.
The main take away is, that the cpu — memory access is always the fastest, when the cpu can access its local memory. NUMA Nodes are CPU/Memory couples. Typically, the CPU Socket and the closest memory banks built a NUMA Node. Whenever a CPU needs to access the memory of another NUMA node, it cannot access it directly but is required to access it through the CPU owning the memory.
Example — 2 Socket machine, 12 Core CPU, 512GB RAM mostly translates to 2 NUMA nodes, each with 1 Socket, 12 Cores, 256 GB RAM.
The performance degradation not being able to access the memory through the local NUMA node can be massive and slowdown the application a lot.
Read the entire article here, VMware vSphere — Why checking NUMA Configuration is so important! – opvizor
Via the fine folks at opvizor.