Licencing SQL Server 2025 in a Virtualised Environment

Software Assurance (SA) is compulsory for SQL Server 2025 Per Core licensing by an individual VM’s virtual cores, but SQL Server can still run in a VM without SA when the deployment is licensed through an applicable physical-server entitlement or Standard Server + CAL model.

The two sections cover different licensing scopes

1. Licensing an individual VM by virtual cores

If licenses are calculated from the VM’s vCores, SQL Server 2025 requires either:

• Perpetual core licenses with active SA, or
• SQL Server subscription licenses.

The VM requires licenses for all allocated virtual cores, subject to a minimum of four core licenses per VM. This applies to both Standard and Enterprise editions. Without SA or a subscription, this particular licensing model is unavailable—the guide’s summary therefore shows “NA” for licensing by VM without SA.^1^

When licensed this way, active SA or subscription rights also permit the licensed virtual operating system environment (OSE) to move between servers within the same server farm as often as needed.

2. Licensing the physical host

This is not the same as assigning a few core licenses to the physical server currently hosting the VM. Under physical-core licensing, sufficient licenses must cover the physical server’s cores, with a minimum of four core licenses per physical processor.^1^

Without SA or a subscription:

• Enterprise Edition: A fully licensed physical server may run SQL Server across physical or virtual OSEs, up to the number of assigned core licenses. For example, 16 assigned Enterprise core licenses permit SQL Server instances across up to 16 OSEs on that licensed server.
• Standard Edition: Physical-core licensing permits SQL Server only in the server’s physical OSE, not in a VM.

With active SA or a subscription, fully licensing a physical server’s cores with Enterprise Edition provides unlimited virtualization rights. Microsoft’s SQL Server 2025 feature documentation also identifies SA as a requirement for Enterprise unlimited virtualization.^2^

Consequently:

What the 90-day rule means

The 90-day provision governs license assignment and reassignment; it does not create eligibility to license an individual VM by vCores without SA.

Without mobility rights, licenses assigned to a physical server generally remain assigned there for at least 90 days. A VM covered by that server’s physical licensing may run only while it remains covered by the assigned host licenses. Moving it to another host does not move those licenses automatically—the destination must already be appropriately licensed, or the licenses must be validly reassigned after the applicable restriction.^3^

This distinction matters in a cluster:

• If every possible destination host is appropriately licensed under a physical-host model, the workload can run on a licensed destination without reassigning the same licenses.
• If only one host is licensed and the VM migrates to an unlicensed host, the VM is not covered merely because fewer than 90 days have elapsed.
• Reassigning the licenses to follow ordinary vMotion or Live Migration events is restricted without the applicable SA/subscription mobility rights.
• The separate License Mobility through Software Assurance benefit concerns deployment on an Authorized Mobility Partner’s shared infrastructure; it should not be confused with routine reassignment inside your own server farm.^4^

Practical conclusion

For SQL Server 2025 Per Core:

• To count only a VM’s virtual cores, obtain SA or subscription licenses.
• Without SA, virtualized production SQL Server is possible through Enterprise physical-host licensing, but the VM remains within that host’s licensed OSE entitlement and does not gain free mobility.
• Standard Per Core without SA cannot use the physical-host route to run SQL Server in a VM.
• Alternatively, Standard Edition can use Server + CAL without SA, with one server license per permitted physical or virtual OSE and CALs for every accessing user or device.

The licensing guide is informational rather than the legal use-rights document. Validate the final design—edition, purchasing program, host core counts, cluster movement, and outsourcing status—against the current Product Terms and the applicable commercial agreement.^3^

References

1. Licensing Resources and Documents
2. Editions and supported features of SQL Server 2025
3. Microsoft Product Terms
4. License Mobility Software Assurance | Microsoft Volume Licensing