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SQL Server Licensing Models

In addition to feature sets, one of the determining factors in choosing a SQL Server edition is cost. With SQL Server 2008, Microsoft provides two types of licensing models: processor-based licensing and server-based licensing.

Processor-based licensing requires a single license for each physical CPU in the machine that is running a Microsoft Server product.

This type of license includes unlimited client device access. Additional server licenses, seat licenses, and Internet connector licenses are not required. You must purchase a processor license for each installed processor on the server on which SQL Server 2008 will be installed, even if some processors will not be used for running SQL Server. The only exception is for systems with 16 or more processors that allow partitioning of the processors into groups so the SQL Server software can be delegated to a subset of the processors.


For licensing purposes, Microsoft bases the number of CPUs in a machine on the number of CPU sockets on the motherboard, not the number of cores on the CPU chip itself. Thus, although a dual-core or quad-core processor chip may appear to the operating system as two or four CPUs, at the time of this writing, each of these types of chips is still considered a single CPU for licensing purposes if it occupies only a single CPU socket on the motherboard.


For those who prefer the more familiar server/client access license (CAL), or for environments in which the number of client devices connecting to SQL Server is small and known, two server/CAL-based licensing models are also available:

  • ​ Device CALs—A device CAL is required for a device (for example, PC, workstation, terminal, PDA, mobile phone) to access or use the services or functionality of Microsoft SQL Server. The server plus device CAL model is likely to be the more costeffective choice if there are multiple users per device (for example, in a call center).
  • User CALs—A SQL server user CAL is required for a user (for example, an employee, a customer, a partner) to access or use the services or functionality of Microsoft SQL Server. The server plus user CAL model is likely to be more cost effective if there are multiple devices per user (for example, a user who has a desktop PC, laptop, PDA, and so forth).


The server/CAL licensing model requires purchasing a license for the computer running SQL Server 2008 as well as a license for each client device or user that accesses any SQL Server 2008 installation. A fixed number of CALs are included with a server license and the server software. Additional CALs can be purchased as needed.


Server/per-seat CAL licensing is intended for environments in which the number of clients per server is relatively low, and access from outside the company firewall is not required. Be aware that using a middle-tier or transaction server that pools or multiplexes database connections does not reduce the number of CALs required.


A CAL is still required for each distinct client workstation that connects through the middle tier. (Processor licensing might be preferable in these environments due to its simplicity and affordability when the number of clients is unknown and potentially large.) The pricing listed in Table 1.2 is provided for illustrative purposes only and is based on pricing available at the time of publication. These estimated retail prices are subject to change and might vary from reseller pricing.

​What is the estimated price of 2008 R2















Web Edition Licensing

The Express Edition of SQL Server 2008 is available via free download from www. microsoft.com/sql. Developers can redistribute it with their applications at no cost by simply registering for redistribution rights with Microsoft. The Express Edition does not require a CAL when it is used on a standalone basis. If it connects to a SQL Server instance running Enterprise Edition, Standard Edition, or Workgroup Edition, a separate user or device CAL is required for the device running Express Edition unless the SQL Server instance it connects to is licensed using the per-processor model.


Developer Edition Licensing

The Developer Edition of SQL Server 2008 is available for a fixed price of $50. The Developer Edition is licensed per developer and must be used for designing, developing, and testing purposes only.


Express Edition Licensing

The Express Edition of SQL Server 2008 is available via free download from www. microsoft.com/sql. Developers can redistribute it with their applications at no cost by simply registering for redistribution rights with Microsoft. The Express Edition does not require a CAL when it is used on a standalone basis. If it connects to a SQL Server instance running Enterprise Edition, Standard Edition, or Workgroup Edition, a separate user or device CAL is required for the device running Express Edition unless the SQL Server instance it connects to is licensed using the per-processor model.


Compact Edition 3.5 Licensing

SQL Server 2008 Mobile Edition is available as a downloadable development product for mobile applications. You can deploy SQL Server Mobile to an unlimited number of mobile devices if they operate in standalone mode (that is, the device does not connect to or use the resources of any SQL Server system not present on the device). If the device connects to a SQL Server instance that is not on the device, a separate user or device CAL is required unless the SQL Server instance it connects to is licensed using the per-processor model.


Choosing a Licensing Model

Which licensing model should you choose? Per-processor licensing is generally required in instances in which the server will be accessed via the Web. This type of licensing includes servers used in Internet situations or servers that will be accessed from both inside and outside an organization’s firewall. Per-processor licensing might also be appropriate and cost effective for internal environments in which there are a very large number of users in relation to the number of SQL Server machines. An additional advantage to the perprocessor model is that it eliminates the need to count the number of devices connecting to SQL Server, which can be difficult to manage on an ongoing basis for a large organization.
Using the server/per-seat CAL model is usually the most cost-effective choice in internal environments in which client-to-server ratios are low.


Mixing Licensing Models

You can mix both per-processor and server/CAL licensing models in your organization. If the Internet servers for your organization are segregated from the servers used to support internal applications, you can choose to use processor licensing for the Internet servers and server/CAL licensing for internal SQL Server instances and user devices. Keep in mind that you do not need to purchase CALs to allow internal users to access a server already licensed via a processor license: The processor licenses allow access to that server for all users.


Passive Server/Failover Licensing

In SQL Server 2008, two or more servers can be configured in a failover mode, with one server running as a passive server so that the passive server picks up the processing of the active server only in the event of a server failure. SQL Server 2008 offers three types of failover support: .

  • Database mirroring
  • Failover clustering
  • Log shipping

​If your environment uses an active/passive configuration in which at least one server in the failover configuration does not regularly process information but simply waits to pick up the workload when an active server fails, no additional licenses are required for the passive server. The exception is if the failover cluster is licensed using the per-processor licensing model and the number of processors on the passive server exceeds the number of processors on the active server. In this case, additional processor licenses must be acquired for the number of additional processors on the passive computer.


In an active/active failover configuration, all servers in the failover configuration regularly process information independently unless a server fails, at which point one server or more takes on the additional workload of the failed server. In this environment, all servers must be fully licensed using either per-processor licensing or server/CAL licensing. Keep in mind that in some log shipping and database mirroring configurations, the standby (passive) server can be used as a read-only reporting server installation. Under this usage, the standby server is no longer “passive” and must be licensed accordingly.


Virtual Server Licensing

Virtualization is defined broadly as the running of software on a “virtual environment.” A virtual environment exists when an operating system is somehow emulated (that is, does not run directly on the physical hardware). When you’re running virtualization software on a system, one or several applications and their associated operating systems can run on one physical server inside their respective virtual environments.


Running SQL Server 2008 inside a virtual operating environment requires at least one license per virtual operating environment. Within each virtual operating environment, the license allows you to run one or more instances of SQL Server 2008. The license for a virtual operating environment can be a server/CAL license or a processor-based license. If using a processor-based license, you must purchase a processor license for each processor that the virtual machine accesses. The total number of physical and virtual processors used by the virtual operating system environments cannot exceed the number of software licenses assigned to that server. However, if you are running Enterprise Edition and all physical processors in the machine have been licensed, you may run an unlimited number of virtual operating environments on that same machine.


Multiple Instances of SQL Server

An option to virtualization is multi-instancing. With multi-instancing, multiple copies of SQL Server can be run concurrently in a single instance of an OS. Multi-instancing for SQL Server 2008 can take place both in a virtual environment or in a physical environment. Although multi-instancing offers a relatively high degree of isolation between copies of SQL Server 2008, this isolation takes place at the application level (instead of at the OS level). In SQL Server 2008, the Workgroup and Standard Editions now allow you to run any number of instances of the server software in one physical or virtual operating system environment on the licensed server. Previously, only the Enterprise Edition of the server license allowed multi-instancing.