PVU in Hyper-V and Nutanix Environments

Eligible technology is the first test

IBM publishes which virtualization technologies qualify for sub-capacity. Hyper-V and Nutanix AHV are eligible when run on supported versions. Running IBM software on ineligible technology voids sub-capacity for that deployment and pushes it straight to full capacity, regardless of how few cores the software actually used.

Hyper-V specifics

On Hyper-V the claim depends on ILMT seeing the host and the virtual processors assigned to each guest.

• ILMT must detect the Hyper-V host and the virtual processors allocated to each VM.
• Cap rules apply where a VM is confined to fewer cores than the host provides.
• Dynamic memory and live migration can move workloads between hosts, and that movement has to be captured in the data.

Nutanix specifics

Nutanix AHV is a KVM based hypervisor. Sub-capacity support depends on the AHV version and, critically, on ILMT holding a working VM manager connection to the cluster. Without that connection ILMT cannot read the virtual layout and falls back to higher counts.

The visibility trap

Both platforms share the same failure point. ILMT reads the virtualization layer through a VM manager connection. If that connection is missing, broken or stale, ILMT cannot prove the virtual cap and defaults to the full physical capacity of the host or, on a clustered configuration, the cluster. A claim you genuinely earned can be lost purely because the data path to ILMT failed.

How to protect the position

Confirm the platform and version are on the eligible technology list, keep the VM manager connection live and monitored, and validate that ILMT reports show the expected virtual cores rather than the physical totals. Reconcile the reported figures against the actual topology every quarter so a silent visibility failure is caught before it becomes a back charge.