Virtualization and partitioning rules are the part of a software license that decides which hardware capacity counts when a program does not run directly on a whole physical server. A virtual machine, a logical partition or a container may be given only a fraction of a host’s cores, but the license may still require the whole host to be counted. Each vendor answers the question differently. Oracle permits only listed hard-partitioning technologies to limit licenses; IBM allows sub-capacity licensing of virtual cores if its License Metric Tool is deployed; Microsoft offers licensing by Individual Virtual OSE and a mobility benefit tied to Software Assurance; Red Hat sells subscriptions that cover a set number of virtual nodes; Broadcom counts every physical core of the host.
These rules are overlays. They do not create new metrics but modify how an existing metric, usually a processor or core metric, is counted. They are also the rules most often at issue when an effective license position is computed for a virtualized estate.
History
The catalog’s dated rules show vendors tightening the evidence required for sub-capacity counting and adding container-specific rules. Oracle’s Partitioning Policy in the catalog states the policies in effect as of 14 February 2022 and is expressly educational: it “may not be incorporated into any contract.”[1] IBM required, effective 10 May 2022, that all Virtual Processor Core licenses using sub-capacity deploy the IBM License Metric Tool (ILMT) or another approved tool; “Manual capacity counting will no longer be permitted.”[2] IBM’s container licensing guide is dated effective January 2022, last updated August 2026.[3] Microsoft’s current Product Terms treat a container as a Virtual OSE for SQL Server.[4]
Scope and definitions
- Hard partitioning physically segments a server. Oracle describes it as a technology that “physically segments a server” and lists approved technologies such as Physical Domains, capped Solaris Zones, IBM LPAR and Fujitsu PPAR.[1]
- Soft partitioning “segments the operating system using OS resource managers.” Oracle’s examples include Oracle VM and VMware.[1]
- Sub-capacity is IBM’s term for licensing the virtual capacity available to a program rather than the full physical capacity of the server.[5]
- Operating system environment (OSE). Microsoft distinguishes a Physical OSE from a Virtual OSE and allocates rights by OSE count.[6]
- Virtual node. Red Hat licenses Red Hat Enterprise Linux Server by “Socket-pair for each Physical Node or 2 Virtual Nodes.”[7]
- License mobility is the right to move a license between hosts, or to a third party’s shared servers, subject to conditions such as a minimum reassignment period.[8]
How it works
Oracle: hard versus soft partitioning
Oracle’s Processor metric counts “all processors where the Oracle Programs are installed and/or running.”[9] Its Partitioning Policy allows exceptions only for approved hard partitioning: “soft partitioning … is not permitted as a means to determine or limit the number of software licenses required for any given server or cluster of servers,” while Oracle-approved hard partitioning technologies “are permitted as a means to limit the number of software licenses required.” Several approved technologies qualify only when capped. The policy also states that with IBM PowerVM Live Partition Mobility, “all cores on both the source and destination servers” must be licensed.[1]
IBM: sub-capacity and ILMT
IBM allows eligible products in eligible virtualization environments to license “the lower of” the maximum virtual cores available to the product at any time and the physical capacity of the host, then convert cores with the PVU table or at 1 VPC per virtual core.[5] Hyperthreading is not adjusted for,[5] and the peak counts: IBM’s terms “do not allow for averaging processor core capacity or temporary spikes in workload.”[5] ILMT or an approved tool is mandatory for PVU, VPC and RVU MAPC sub-capacity; failure results in “charging under full capacity for the total number of physical processor cores activated and available for use on the server.”[2]
Microsoft: physical cores, Virtual OSEs and mobility
Microsoft offers two ways to license core-based server products. Licensing by physical core covers the host: Windows Server Datacenter “permits use of the server software in any number of OSEs on the Licensed Server,” while Standard permits two OSEs, plus the Physical OSE if it only hosts and manages the virtual ones, and can be stacked for two more OSEs at a time.[6] Licensing by Individual Virtual OSE, available only with subscription licenses or active Software Assurance, counts the Virtual Cores in each Virtual OSE, with a minimum of 8 licenses per Virtual OSE for Windows Server and 4 for SQL Server.[6][4]
Mobility depends on Software Assurance. Within a server farm, SQL Server licenses may be reassigned as often as needed, but moves between farms are not allowed within 90 days of the last assignment.[4] License Mobility through Software Assurance lets a customer move eligible licensed software to shared servers at Microsoft Azure or a qualified partner, after submitting a verification form, and not back within 90 days; each SQL Server Core License with SA covers one virtual core, with a minimum of 4 cores per OSE. Windows Server is not eligible.[8] The separate Flexible Virtualization Benefit allows software under subscription or SA to run on shared servers of Authorized Outsourcers.[10] SQL Server fail-over rights, also an SA benefit, grant passive Fail-over OSEs that may not serve data, and do not apply under License Mobility.[4]
Red Hat: virtual nodes and portability
Red Hat counts virtual deployments in nodes rather than cores. One RHEL Server subscription covers a physical node of up to two sockets or two virtual nodes.[7] RHEL for Virtual Datacenters covers “Unlimited Virtual Nodes running on a Socket-pair,” but does not include the host operating system.[7] Red Hat’s subscription guide allows a socket-pair subscription to be converted to cover two virtual instances and back “without changing subscription terms, purchasing additional subscriptions, or notifying Red Hat.”[11]
Broadcom: the host is the unit
Broadcom’s VMware licenses are themselves the virtualization layer, and they count the physical host. Every core on the server where the software is installed must be licensed, with a 16-core-per-processor minimum, and all components of the software “may only be utilized on, or for, the same physical Cores where the vSphere component in Software Core license is deployed.” A hardware partition or blade is a separate hardware system.[12] Porting VCF to a cloud is permitted only to Certified Cloud Services and does not convert cores to vCPUs.[12]
Device and user metrics in virtual environments
Virtualization also changes device counts. Adobe counts each virtual environment, “including virtual machines and virtual processors,” as a separate Computer.[13] Autodesk’s Virtualization Policy allows virtualized installation for Single User, Flex and Token Flex purchases, but not for the retired multi-user offering, and states that “only one authorized user can access a single license at a time.”[14] SAP’s Cores metric counts virtual cores, and “If the licensed Software will run in a pure virtual environment, physical Cores will not be counted.”[15]
Containers
Container rules are newer and differ from VM rules. Microsoft treats a container as a Virtual OSE and requires a Core License for each hardware thread mapped to a container where hyperthreading is enabled, subject to the minimum of four.[4] IBM’s container licensing counts the sum of pod CPU limits, capped at worker-node capacity, aggregated at cluster level and rounded up, with hyperthreading factors that apply to containers only.[3] The PVU table does not apply: IBM sets “70 PVUs per Virtual Processor Core (VPC) or virtual CPU (vCPU).”[3] IBM License Service is “the only accepted tool” for container licensing, with “no exceptions.”[3] Red Hat’s Core definition includes a virtual core “supporting a container,” and its OpenShift Core-pair counts 2 physical cores or 4 vCPUs.[7][16]
Vendor comparison
| Vendor | Rule | Kind | Summary | Effective |
|---|---|---|---|---|
| Oracle | Hard partitioning / soft partitioning | Partitioning | Only approved hard partitions limit processor counts[1] | 2022-02-14 |
| IBM | PVU sub-capacity — lower of virtual vs physical | Virtualization | Lower of virtual cores and host capacity[5] | 2026-08-31 |
| IBM | ILMT mandatory for sub-capacity (PVU / VPC / RVU MAPC) | Restriction | ILMT required or full capacity applies[2] | 2022-05-10 |
| IBM | Container vCPU Capacity Counting Methodology | Counting | Pod CPU limits, cluster round-up[3] | 2026-08-01 |
| IBM | Container — PVU table does not apply; 70 PVU = 1 vCPU | Counting | 70 PVU = 1 vCPU in containers[3] | 2026-08-01 |
| IBM | Container Licenses — IBM License Service mandatory | Restriction | IBM License Service mandatory[3] | 2026-08-01 |
| Microsoft | Windows Server Datacenter unlimited OSEs | Virtualization | Any number of OSEs when all cores licensed[6] | 2026-08-10 |
| Microsoft | Windows Server Standard OSE allotment | Virtualization | Two OSEs per full licensing, stackable[6] | 2026-08-10 |
| Microsoft | Windows Server by Virtual OSE floor | Floor / minimum | 8 licenses per Virtual OSE[6] | 2026-08-10 |
| Microsoft | License Mobility through Software Assurance | Mobility | Shared servers with SA; 90-day moves; 4 cores per OSE[8] | 2026-08-10 |
| Microsoft | Flexible Virtualization Benefit | Virtualization | Authorized Outsourcers’ shared servers[10] | 2026-08-10 |
| Microsoft | SQL Server fail-over (passive) rights | Restriction | Passive Fail-over OSEs with SA[4] | 2026-08-10 |
| Red Hat | RHEL Server — Socket-pair per Physical Node or 2 Virtual Nodes | Counting | Socket-pair or 2 virtual nodes[7] | 2026-02-01 |
| Red Hat | RHEL for Virtual Datacenters — unlimited Virtual Nodes on a Socket-pair | Virtualization | Unlimited virtual nodes per Socket-pair[7] | 2026-02-01 |
| Red Hat | Physical↔virtual portability (Socket-pair ↔ 2 Virtual Guests) | Mobility | Socket-pair converts to 2 virtual instances[11] | 2025-11-04 |
| Broadcom | BIOS-deactivated Cores must be licensed | Counting | All host cores, incl. BIOS-disabled[12] | 2026-06-19 |
| Broadcom | License Portability — Certified Cloud Services only; no Core→vCPU | Cloud / BYOL | Certified Cloud Services only; no core-to-vCPU[12] | 2026-06-19 |
| Adobe | Each virtual environment counts as a Computer | Virtualization | Each VM is a Computer[13] | 2024-06-18 |
| Autodesk | Virtualization policy by purchase type | Virtualization | Allowed by purchase type[14] | 2026-08-31 |
| Citrix | NetScaler vCPU checkout by running CPUs | Counting | NetScaler VPX checks out running vCPUs only[17] | 2026-06-17 |
The metrics these rules modify include Oracle Processor, Microsoft Per Core and Per Core/CAL, IBM Processor Value Unit (PVU) and Virtual Processor Core (VPC), Red Hat Virtual Node and vCPU, SAP Cores, Broadcom per Core and Adobe Computer. Program-level overlays are Microsoft License Mobility through Software Assurance, IBM Container Licenses and Broadcom License Portability.
Relationship to other license models
The same overlays reappear in public clouds, where vendors publish vCPU mappings instead of partitioning rules. Oracle’s cloud licensing document counts two vCPUs as one Processor license when multi-threading is enabled and states that the core factor table does not apply in Authorized Cloud Environments.[18] Those mappings are covered in Cloud BYOL and authorized cloud environments. Virtualization also affects concurrent and device licensing, where each virtual machine may count as a device, and subscription and consumption licensing, where Microsoft’s Virtual OSE and mobility rights depend on subscription or Software Assurance.[6]
Criticism and challenges
Virtualization rules create the largest differences between vendors for the same infrastructure. A cluster running both Oracle and IBM software can be licensed on virtual capacity for IBM if ILMT is deployed, but on all physical cores of every host for Oracle unless an approved hard partition is used.[5][1] Oracle’s policy is educational and not contractual, which leaves its status to the executed agreement.[1] Live migration is a further difficulty: Oracle requires both source and destination servers to be licensed under PowerVM Live Partition Mobility, and Microsoft restricts license moves between server farms to once every 90 days.[1][4] Container counting depends on tooling that must be in place before deployment, since IBM accepts no substitute for License Service.[3]
Out of scope
This article does not cover hypervisor feature comparisons, performance sizing, or hyperscaler instance pricing. Vendor-specific procedures are on Oracle Database licensing, Windows Server licensing, SQL Server licensing, IBM Passport Advantage licensing, Red Hat Enterprise Linux and OpenShift subscription licensing and VMware vSphere and VMware Cloud Foundation licensing.