Licensing SQL Server 2014 for High Availability

Licensing SQL Server 2014 for High Availability

Today, more and more SQL Server’s are being deployed in a High availability scenario,  using various technologies available, such as Database Mirroring, Log shipping, Hardware Clustering, Replication or Always On availability groups. In some cases, SQL Server’s are being deployed on a Virtual Machine, which in itself is highly available.

Let’s talk about the various scenario’s in HA & DR with SQL Server and how to properly license them.

You need to buy Software Assurance for all SQL Server’s which needs to have a “Warm” passive server for failover purposes. The SA (Software Assurance) benefit will ensure “License Mobility Rights” so that you do not need to buy additional licenses for the failover partner.

Note: You cannot run any workloads(Reporting, Querying etc.) on the secondary server. If you do, you need to “Fully” license the second SQL Server. Only Standby servers are supported.

Source: Microsoft Licensing Guide for SQL 2014

In the following scenario, One location is covered under the SA benefit. However, since there are 2 secondaries, you need to purchase the required number of licenses for maintaining two DR sites.

Source: Microsoft Licensing Guide for SQL 2014

Licensing SQL Server 2014 under the Per Core model:

• The Server which has more CPU Cores needs to be covered under the Core based licensing method.
• If your primary server has 6 core, and the secondary passive site has 8, you need to buy 8 licenses with Software assurance to cover both the installations.
• In case of a failover, the License is dynamically assigned to the secondary server under the “License Mobility Rights”
• In case of Always On Availability groups, all SQL Servers servicing active server workloads needs to be fully licensed.

For Always On Availability Groups, if the Secondaries are using “Read Intent”, “Read-Only” or “Backup Server”, then they need to be fully licensed.