SQL SERVER – Understanding Licensing Models

SQL Server offers several licensing models designed to meet a variety of deployment needs. With modern versions of SQL Server (such as SQL Server 2019 and SQL Server 2022), the licensing structure has evolved to reflect advances in technology and diverse use cases. Below are the primary licensing models available:

Core-Based Licensing Model

Under the core-based licensing model, each physical or virtual core running SQL Server must be licensed. A minimum of four core licenses is required per physical processor, regardless of the number of cores. This model is ideal for:

• Deployments involving high numbers of users or devices, such as web-based applications accessible from the Internet.
• Environments with unpredictable or fluctuating usage.
• Scenarios where scalability and flexibility are key.

To license SQL Server under this model:

1. Count the total cores in the server or virtual machine.
2. Purchase a core license for each core, with a minimum of four cores per processor.

Server + Device CAL Licensing Model

The Server + Device Client Access License (CAL) model requires:

• A separate server license for each SQL Server instance.
• A device CAL for each client device accessing SQL Server.

This model is cost-effective for environments where:

• A limited number of devices connect to SQL Server.
• SQL Server operates within a controlled Intranet or behind a firewall.
• Multiple users share a single device to access SQL Server.

Server + User CAL Licensing Model

The Server + User CAL model also requires:

• A separate server license for each SQL Server instance.
• A user CAL for each individual user accessing SQL Server.

This option is ideal for scenarios where:

• A limited number of users access SQL Server.
• Each user connects using multiple devices (e.g., desktop, laptop, mobile).

Key Considerations for SQL Server Licensing

1. Virtualization and Cloud Scenarios: For virtual environments, core-based licensing provides more flexibility. For cloud-based deployments, consider Azure SQL or other hosted options for simplified management.
2. High Availability: Additional licensing may be required for high-availability setups like Always On Availability Groups. Check Microsoft’s official licensing documentation for specific guidance.
3. Compliance: Always ensure compliance with Microsoft’s licensing terms to avoid potential audits or penalties.

For the most accurate and detailed information, refer to Microsoft’s SQL Server Licensing Guide or consult with a licensing expert.

Reference: Pinal Dave (https://blog.sqlauthority.com)