Compare virtual NUMA topology with the host before changing memory placement

Source facts

Microsoft exposes host NUMA-node information through Get-VMHostNumaNode, including logical cores and memory available per node. A VM’s virtual NUMA configuration controls node count, processors per node, and memory per node. By default, the VM uses the host’s topology. The host NUMA-spanning setting applies only where the host has multiple NUMA nodes. Microsoft documentation.

Applicability

Identify the physical topology, guest workload, current virtual topology, memory configuration, and intended migration hosts. Review the source’s platform requirements and the application’s NUMA guidance before changing placement settings.

DSE recommendation

Create a host-to-VM topology comparison and record the problem the proposed change is intended to address. Ask the application and virtualization owners to review node size and memory assumptions. Preserve the original configuration and define a representative workload measurement before making an adjustment.

Verification

Inspect the VM’s exposed topology and compare its placement with the approved design. Use the documented performance counters and application measurements during a controlled workload run. Record the physical host used for each test and revisit the result if the VM moves to a materially different topology.

Official references

Microsoft Learn: Configure NUMA to Optimize Hyper-V Memory. Source reviewed September 8, 2026.