Key Points for EC2 SQL Server HA Standby Node License Cost Reduction

Amazon EC2 High Availability for SQL Server can provide license cost reduction for eligible SQL Server HA standby nodes. However, this cost reduction has strict prerequisites — notably, the standby node cannot carry active workloads or serve as a readable secondary replica for queries.

Prerequisites

Before enabling SQL Server HA license savings, confirm the environment meets the requirements:

• Windows Server 2019 or later.
• SQL Server 2017 or later.
• An HA cluster supports only two EC2 nodes.
• Instances need to run SSM Agent.
• Instance IAM Role needs EC2 SQL HA and SSM-related permissions.

If the environment is still on Windows Server 2016, or the cluster has more than two nodes, the prerequisites for this feature are not met.

Standby Node Restrictions

To qualify for license cost reduction, the standby node must remain passive:

• It does not process incoming business traffic.
• It does not run active SQL Server workloads.
• It cannot serve as a readable secondary replica to handle read queries.
• It should not run standalone databases outside the availability group.

The core determination is simple: as long as the node is providing data services, it is no longer a pure standby.

Readable Secondary Affects Cost Reduction

When Readable Secondary is enabled in an Always On availability group, the secondary replica can be accessed by applications, reports, or manual queries. Under license logic, this constitutes active use and requires full SQL Server licensing.

Therefore, if the goal is to obtain the standby node license cost reduction, do not enable readable secondary replicas.

Does Backup Require a Readable Secondary?

No. SQL Server supports executing certain backup scenarios on non-readable secondary replicas. In other words, for full backups and log backups, there is no need to set the secondary replica as readable.

Before actual configuration, verify against the SQL Server version and availability group backup preferences.

Enablement Steps Overview

1. Confirm SSM Agent Is Online

aws ssm describe-instance-information

The instance should show PingStatus: Online.

2. Configure IAM Permissions

Attach the following to the instance profile:

• AmazonSSMManagedInstanceCore
• AWSEC2SqlHaInstancePolicy

3. Prepare SQL Credentials

By default, NT AUTHORITY\SYSTEM can be used to read SQL Server HA metadata. If the environment restricts this account, place the SQL Server credentials in Secrets Manager and specify them during enablement.

4. Enable in the EC2 Console

In the EC2 console, select the HA cluster-related instances and navigate to:

Actions -> Instance settings -> Modify SQL High Availability settings

Check the prerequisites, and enable license savings after they pass.

After enabling, you should see:

• Primary node: Active / Full license included
• Standby node: Standby / Waived

Summary

SQL Server HA standby node license cost reduction is not a simple toggle. What truly matters is that the standby node must remain passive.

If you enable a readable secondary for queries, reports, or application reads, you lose the cost reduction eligibility. For backup scenarios, prioritize using SQL Server's supported secondary replica backup capabilities rather than turning the standby node into a readable workload node.