Microsoft SQL Server licensing can be complicated and even a little overwhelming at times. The purpose of this post is to cut through that complexity at an introductory level and then delve deeper in future posts.

What SQL Server 2016 Editions are currently available?

The previous release of SQL Server 2014 was commercially available in four editions:

Enterprise edition – recommended for use with mission critical applications and large scale data warehousing
Business Intelligence edition – provides premium corporate and self-service business intelligence (BI)
Standard edition – delivers basic database, reporting and analytics capabilities
Developer – is a full-function version of SQL Server software—including all of the features and capabilities of Enterprise Edition—licensed under the Developer Tools model, which is a “per user” model

This has been streamlined with the 2016 release and now is available in three commercial editions:

Enterprise edition
Standard edition
Developer

The key difference here being that the licensing and product function of Business Intelligence edition has been absorbed into the Enterprise edition.

Note: SQL Server Express is available as a free download from Microsoft, but it must be noted there are limitations on its supported system requirements. For an overview of the available editions and supported scale of SQL Server, click here.

How are SQL Server licenses sold?

The software licensing options remains the same for SQL Server 2016 as previously available e.g. Server + CAL or Per Core. It must be noted however that the Enterprise edition is only available under the Per Core model.

SQL Server – Per Core Based Licensing

The Per Core licensing option allows for unlimited users or devices to access SQL Server (both internally and externally). The major benefit of this option is that there is no requirement to try to quantify the number of users or devices accessing the SQL Server, be that direct or via indirect means (multiplexing).

Note: When running SQL Server in a physical environment, licenses must be assigned to all of the physical cores on the server. A minimum of four core licenses per physical processor are required, with licenses being sold in packs of two.

So how many licenses do I need? The process to determine this is relatively straight forward:

Example 1 – This SQL Server has two processors, each with six cores:

Ascertain how many cores there are per processor (keeping in mind the minimum requirement of four cores per processor)
Count the total number of cores
A total of twelve cores are present, therefore 6 SQL Server Per Core licenses (packs of 2) are required

The Per Core option is often the preferred licensing option when:

The SQL Server is external facing and an unquantified number of users or devices access the server
Deploying SQL Server Enterprise – the Standard edition does not support the Per Core licensing option
The cost of licensing SQL Server Standard is too high based on server access

SQL Server – Server + CAL Licensing

When licensing SQL Server Standard under the Server + CAL option, customers must assign a license to the physical server hosting any operating system environment (OSE) running SQL Server and acquire a SQL Server CAL for each user or device that accesses the server.

Note: The SQL Server license allows unlimited SQL instances to be deployed on the OSE (physical or virtual).

The Server + CAL option is often the preferred licensing option when:

Smaller SQL Server implementations exist and SQL is the supporting database for another application or smaller Intranet; and
The number of users or devices accessing SQL Server can be quantified and Server + CAL is more cost effective than the Per Core model