Hi members group,
I have a question. I read document for performance best practices, page 53 have talk to Virtual NUMA.
CPU Hot Add is a feature that allows the addition of vCPUs to a running virtual machine. Enabling this
feature, however, disables vNUMA for that virtual machine, resulting in the guest OS seeing a single
vNUMA node. Without vNUMA support, the guest OS has no knowledge of the CPU and memory
virtual topology of the ESXi host. This in turn could result in the guest OS making sub-optimal scheduling
decisions, leading to reduced performance for applications running in large virtual machine.
For this reason, enable CPU Hot Add only if you expect to use it. Alternatively, plan to power down the
virtual machine before adding vCPUs, or configure the virtual machine with the maximum number of
vCPUs that might be needed by the workload. If choosing the latter option, note that unused vCPUs incur
a small amount of unnecessary overhead. Unused vCPUs could also cause the guest OS to make poor
scheduling decisions within the virtual machine, again with the potential for reduced performance.
https://www.vmware.com/docs/vsphere-esxi-vcenter-server-67u2-performance-best-practices
So if adding hot memory will reduce performance? Because the document only mentions CPU host add.
Thanks !