SQL Server 2012 Virtualization Licensing Guide

Licensing SQL Server 2012 for Virtualization

SQL Server 2012 offers customers a unique level of flexibility when licensing in virtual environments—with
options to license for maximum/unlimited virtualization or to carve out just the computing power needed by
licensing individual virtual machines (VMs). In this document, we will cover each of these options in detail and
the related licensing rules. First, let’s start with a brief overview of these two paths.

SQL Server 2012 Virtualization – Licensing Individual Virtual Machines

Microsoft offers the unique option to license VMs individually. This is in contrast to other database vendors
in the industry that usually require customers to license the entire server, even when the workload utilizes
only a fraction of the available computing power. The option to license individual VMs is designed to help
organizations use hardware resources more cost-effectively by carving out and paying for just the computing
power that is needed. SQL Server can be licensed in individual VMs using the “Per Core” or the “Server+CAL”
licensing model.
●● Per Core Licensing Model: Purchase a core license for each virtual core (or virtual processor/virtual CPU/
virtual thread) allocated to the VM, subject to a four core license minimum per VM.
●● Server+CAL Licensing Model: SQL Server 2012 Business Intelligence and Standard Edition customers
purchase one server license for each VM running SQL Server software. In this model, each user or device
accessing SQL Server 2012 must also be licensed.
Note that individual VMs may be licensed for SQL Server 2012 Enterprise Edition through the Server+CAL
model. See page 8 for more details.

SQL Server 2012 Virtualization Licensing for Maximum Virtualization

●● Deploy an Unlimited Number of VMs: SQL Server 2012 Enterprise Edition customers who have licensed
all of the physical cores on the server and have Software Assurance (SA) coverage may deploy any number
of VMs on that server.
●● SQL Server 2012 Enterprise Edition customers who have licensed all the physical cores on the server but
who do not have SA coverage, can deploy a number of VMs equal to the number of core licenses assigned
to the server.

●● For more information on these licensing options, refer to the SQL Server 2012 Licensing Guide,
which can be found here: http://go.microsoft.com/fwlink/?LinkId=230678

Next, we will discuss these licensing rules in more detail and walk through a few use cases to help illustrate how
these can be applied in real-world scenarios.

Scenario 1: Server Consolidation

SQL Server 2012 Virtualization – Licensing Individual VMs

Server consolidation has been a major driver of virtualization in today’s IT environments. Virtualizing workloads
and consolidating them onto fewer physical servers can improve hardware utilization and reduce server hosting
and administration costs.
As an example, consider a manufacturing company that has a reporting workload running on a SQL Server
2012 database, hosted on a dedicated server. Similarly, the company has CRM and HR applications built on
SQL Server databases, and each running on their own dedicated server. After purchasing new high capacity
hardware, the company decides to virtualize these three workloads and move them to a single server.

In this scenario, the company chooses to license each VM individually. This provides the flexibility to license only
the computing power required by each SQL Server workload. Let’s look in depth at how to license individual
VMs in this example using each of the available licensing models.

Licensing Individual VMs in the Per Core Model
To license each of these VMs in the Per Core licensing model, this customer must purchase a core license for
each virtual core allocated to the VM. Consistent with Per Core licensing in the physical environment, there
is a four core minimum license requirement for each VM. (Note that for licensing purposes, a virtual core is
equivalent to a virtual thread and may also be referred to as a virtual processor or virtual CPU.)
To illustrate this, we’ll continue with our manufacturing company example in which three workloads have been
virtualized and consolidated on a single server. In this example, these workloads are static and will remain on
the server.

The company needs to determine its virtual licensing requirements based on the number of virtual cores in
each VM. As you can see in the graphic above:
●● The first VM with two virtual cores requires four core licenses to meet the four core minimum requirement.
●● The second VM requires four core licenses, one for each virtual core.
●● The third VM requires six core licenses.
As a result, the company purchases a total of 14 core licenses, which are sold in 2-core packs.
Note that when licensing individual VMs, core factors do not apply as they would when licensing non-virtual
deployments.

Hyper-threading
For customers using Intel’s hyper-threading technology to split a single, physical core into two separate threads
of power, there are some additional factors that should be kept in mind when licensing individual VMs using
the Per Core Model.

1. When hyper-threading is turned on, a core license is required for each thread supporting a virtual core. In
   the example below, hyper-threading is enabled for the physical processor supporting a VM. Since hyperthreading
   creates two hardware threads for each physical core, a total of 8 core licenses would be required
   in this scenario. A core license allows a single virtual core to be supported by a single hardware thread.
2. Conversely, if a single hardware thread is supporting multiple virtual cores, a core license is still required
   for each virtual core.

It should be noted that a customer could license all the physical cores in the server with Enterprise Edition and
Software Assurance to gain use rights for unlimited virtualization. This option may be more cost effective and
provide greater deployment flexibility. (We will cover this topic in more detail later in the document.)
●● Note: For customers with versions prior to SQL Server 2012, please refer to the appendix of this
document for information on licensing options and rules.

Licensing Individual VMs in the Server+CAL Model
Many customers license SQL Server using the Server plus Client Access License (Server+CAL) licensing model,
which is based on the users or devices accessing the software. As introduced earlier, these customers can
license for virtualization by purchasing one server license for each VM that is running SQL Server software.
When licensing VMs, customers can assign multiple server licenses to a single physical server (one for each VM
running on that server).

Continuing with our manufacturing company example, let’s assume that in this case the instances of SQL Server
in the physical environment had been licensed under the Server+CAL licensing model. Now, three server
licenses will be required for the virtual environment—one for each virtual machine (in this case, one Business
Intelligence Edition server license and two Standard Edition server licenses). This is true regardless of the
number of virtual processors allocated to the VM. In addition, each user or device accessing SQL Server 2012
software requires a SQL Server 2012 CAL. Note: SQL Server CALs allow access to multiple VMs.

SQL Server 2012 Enterprise Edition Server+CAL Customers
Even though the Server+CAL licensing model is no longer available for Enterprise Edition with the release of
SQL Server 2012, many customers are able to upgrade their existing units through Software Assurance or can
continue to purchase Enterprise Edition server licenses through their Enterprise Agreements. Customers who
have deployed the SQL Server 2012 Enterprise Edition in the Server+CAL model are eligible to license up to
four VMs for each Enterprise Edition server license. These customers can assign multiple Enterprise Edition
server licenses to a single server to deploy additional VMs. It’s important to note that each Enterprise Edition
server license is limited to a total of 20 hardware threads of power across the (four or fewer) VMs for which it
is licensed. Multiple licenses can be used to add more VMs but not to increase the amount of compute power
used by a single OSE.
See the table below for the number of VMs per server license for each SQL Server 2012 edition.

Licensing individual VMs is a great option for organizations that want the flexibility to carve out and license
the needed computing power from their hardware. However, as virtual environments become more dynamic
and utilize more servers, this may also create a complex set of licensing requirements that must be monitored
to ensure compliancy. Next we will discuss how to license SQL Server in more dynamic virtual environments
where licensing requirements change frequently to meet shifting business needs.

Scenario 2: Dynamic Virtual Environments

Many organizations have virtual computing environments that are dynamic—meaning that the virtual
environments are spread across multiple virtual servers, and VMs are moved across these servers occasionally
to reallocate resources. In some cases, VMs are moved dynamically by the hypervisor. These dynamic scenarios
can make software licensing more complicated, depending on how customers choose to license their virtual
workloads. To help simplify licensing for these scenarios and to provide greater flexibility, Microsoft offers
License Mobility within server farms, which allows licenses to move between servers along with the VMs.

SQL Server 2012 Virtualization – License Mobility

License Mobility is a benefit available for any edition of SQL Server with Software Assurance coverage. License
Mobility offers a great advantage to customers who license individual VMs and then need to reassign those
licenses to different servers to accommodate moving workloads.
To help understand how License Mobility can be put into practice, consider our manufacturing company
example. As the company grows, it adds more physical servers and begins to multiply its workloads across
additional VMs. To maximize server utilization, the company periodically “moves” its VMs to different physical
servers in its datacenter.

With License Mobility, this company is able to reassign licenses to different servers within the server farm as
often as is needed. So any time one of these VMs moves to a different server, the license moves with it. This can
provide significant cost savings as well as simplicity in licensing. Without License Mobility, the company could
only move licenses to a different server once every 90 days, which for this example means the company would
need to maintain enough licenses on each server to cover the peak number of VMs that could be moved to
the server at any time.
Another scenario in which License Mobility can help save costs is when organizations host virtualized workloads
both in their datacenters and in the public cloud. As these “hybrid” IT infrastructures grow and become more
dynamic, customers can move a workload to a VM role in the cloud and seamlessly move the license with it.
License Mobility provides the flexibility to help address this need.
License Mobility is available for any edition and any version of SQL Server with active SA coverage, and it is
available for licenses under both the Per Core and Server+CAL license models.
There are a few additional considerations to be aware of with License Mobility:

1. As mentioned earlier, customers with SQL Server Enterprise Edition Server+CAL licenses can license up to
   four VMs per server. If customers intend to use this licensing model in a dynamic environment, it’s important
   to note that to gain the benefits of License Mobility, the VMs licensed with a single Enterprise Edition server
   license must move together to the same server at the same time. This may not always be possible, in which
   case customers must assign one Enterprise Edition server license to each VM being deployed.
2. A server farm may consist of up to two data centers located in time zones that are within four hours of one
   another and/or with the European Union (EU) and/or European Free Trade Association (EFTA).
   ●● For more detailed information on License Mobility, refer to the SQL Server 2012 Licensing Guide,
   which can be found here: http://go.microsoft.com/fwlink/?LinkId=230678
   Today, many virtual environments are becoming even more dynamic, especially in scenarios where software is
   used to automatically and dynamically allocate resources to different VMs “on the fly”. In the next section, we
   will discuss licensing SQL Server in these scenarios and look at ways to further simplify licensing management.

Scenario 3: High Volume Dynamic Virtual Environments

SQL Server 2012 Virtualization – Licensing for Maximum Virtualization

For organizations with a large number of VMs and complex, highly dynamic virtual environments, Microsoft
offers the option to license for maximum virtualization. This means that when all of the cores on a server are
licensed and covered with Software Assurance, a customer can deploy any number of VMs on the server.
The key benefits of licensing for maximum virtualization are simplicity and potential cost savings. Maximum
virtualization ensures that customers are covered, without needing to be concerned with tracking individual
VMs or the amount of power assigned to each VM. This is especially relevant for private cloud scenarios with
a large number of VMs being moved dynamically between different physical servers, when self-provisioning is
enabled, or when hyper-threading is turned on.
As an example of how maximum virtualization can be employed, let’s look at a scenario using the HP Enterprise
Database Consolidation (DBC) Appliance. The Enterprise DBC Appliance enables the consolidation of hundreds
of databases into a single virtual environment through an integrated hardware and software solution.

In this scenario, an organization has deployed the base configuration of the Enterprise DBC Appliance, in which
the physical servers are combined as a pooled virtual resource that supports a large number of VMs. Further
complicating this scenario for licensing purposes is that the VMs are being moved dynamically between the
server blades in the appliance to maintain peak performance.
By licensing all of the physical cores in the appliance, and covering those licenses with Software Assurance,
the organization can deploy an unlimited number of VMs. This can dramatically simplify licensing, as the
organization can be assured that all VMs are correctly licensed, even when they are dynamically moved across
the different servers in the appliance. The customer can also spin up as many new VMs as they need without
ever needing to buy additional licenses.
One important factor when licensing for maximum virtualization is to determine which use rights apply. When
deploying VMs on a server, the use rights of the most recent licensed version apply to every VM on the server.
For instance, if a customer is using SQL Server 2008 R2 processor licenses (with Software Assurance), to license
for maximum virtualization and upgrade any of the VMs to SQL Server 2012, SQL Server 2012 use rights would
now apply for every VM running on that server.
In scenarios like this one, it may still be possible to license VMs individually but it is likely to be difficult to
manage. There are a few caveats to consider when licensing individual VMs in highly dynamic environments.

●● SQL Server 2012 Enterprise Edition Server+CAL Customers
As mentioned earlier, in dynamic environments like this, customers would need to assign an Enterprise
Edition server license to each VM to ensure that they are properly licensed at all times. While customers can
license up to four VMs with a single Enterprise Edition server license, as VMs are moved dynamically in this
scenario, it would be impossible to ensure that all four VMs move together across the servers. In this case,
License Mobility will not work and it is strongly recommended that one Enterprise Edition server license is
assigned to a single VM.

●● Dynamically changing power usage in VMs
In some scenarios, the power allocated to each VM is scaled up and down dynamically to meet the changing
needs of the workload and to maximize server utilization. In this case, it may be impossible to track virtual
core-based usage if customers license individual VMs with core licenses.

SQL Server 2012 Virtualization Rights for Prior Software Releases

The following overview summarizes the software virtualization rights for current and prior versions, editions
and licensing models of SQL Server software. This summary should not be a substitute for careful review and
understanding of your rights and obligations as described in your Microsoft Volume Licensing agreement
and the Product Use Rights. When reviewing virtualization rights for prior versions, it’s important to keep two
things in mind:

1. Product use rights for the originally licensed version and edition apply even if using downgrade or crossedition
   deployment rights. For example, if a customer purchases a SQL Server 2012 license, SQL Server
   2012 use rights apply even if the customer deploys SQL Server 2008 R2 (or an earlier version).
2. If customers (who are eligible through SA), have upgraded from a previous version, the product use rights
   for the version running apply. For example, if a customer upgrades from SQL Server 2008 to SQL Server
   2012, SQL Server 2012 use rights apply.
3. License Mobility moved to an SA benefit with the release of SQL Server 2012. So any license covered with
   SA, regardless of which version or edition of the software is deployed, will have License Mobility rights.

*Additional Notes When Licensing Individual VMs:
Under the Server+CAL licensing model, SQL Server CALs are required for any user or device accessing SQL
Server functionality or data, regardless of whether SQL Server or any of its components are running a physical
or virtual OSE.
When licensing individual VMs under the Per Processor licensing model, all virtual processors (v-cores)
supporting the VM must be licensed. No additional CALs are required. For licensing purposes, a virtual processor
maps to a core (when hyper-threading is turned off) or hardware thread (when hyper-threading is on). To
calculate the number of processor licenses required for each VM, divide the number of virtual processors in the
VM by the number of physical cores (or threads) per physical processor. If this results in a fraction, round up to
the next whole number.
When licensing individual VMs under the Per Core licensing model, all virtual cores supporting the VM must
be licensed, with a minimum of four core licenses required. No additional CALs are required. For licensing
purposes, a virtual core maps to a core (when hyper-threading is turned off) or a hardware thread (when hyperthreading
is on).

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