Easiest Way to Configure SQL Server Always On for Azure VMs

Updated at: 16/07/2025

Maximize SQL Server availability and resilience with Azure VMs using Always On Availability Groups. This guide simplifies the complex setup, walking you through the easiest configuration steps. We'll cover prerequisites, crucial settings, and best practices, ensuring high availability and minimal downtime. Learn to protect your data and maintain business continuity effortlessly, even during unexpected outages. Let's get started!

Step-by-Step Instructions

  1. Search and Select SQL Server VMs

    • Navigate to the search bar and enter 'Azure SQL'.
    • Select 'SQL Server virtual machines'.
    Select 'SQL Server virtual machines'. Select 'SQL Server virtual machines'.
    Search and Select SQL Server VMs

  2. Enable High Availability and Choose License

    • Ensure the high availability checkbox is selected.
    • Select your preferred SQL Server license and click 'Create'.
    Select your preferred SQL Server license and click 'Create'. Select your preferred SQL Server license and click 'Create'.
    Enable High Availability and Choose License

  3. Provide Basic VM Details

    • Provide details such as Resource Group name, region, availability options, image size, username, password, and public inbound ports.
    Provide details such as Resource Group name, region, availability options, image size, username, password, and public inbound ports.
    Provide Basic VM Details

  4. Configure Always On Cluster Settings

    • Provide cluster name and a storage account.
    • Enter domain username and credentials.
    • Specify the resource group name and listener.
    Specify the resource group name and listener. Specify the resource group name and listener. Specify the resource group name and listener.
    Configure Always On Cluster Settings

  5. Review and Deploy

    • Review and create the deployment.
    Review and create the deployment.
    Review and Deploy
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Tips

  • Revisit preceding steps to locate errors during deployment.
  • Ensure the Ada user account has necessary permissions to create a cluster.
  • Ensure the NT Authority system account is added to all AG nodes.
  • Ensure ports required for SQL Server Always On Availability Groups are not blocked in firewalls, NSGs, or OS, and are not in use by other SQL Server instances or applications.
  • If more than one node per subnet, configure an Azure Load Balancer and proper port for the Azure SQL Server Availability Group DNN listener.

Common Mistakes to Avoid

1. Incorrect Network Configuration

Reason: Insufficient network bandwidth or improper firewall rules can prevent communication between the Always On Availability Group (AG) replicas, leading to connection failures and potential data loss.
Solution: Ensure sufficient network bandwidth, open necessary firewall ports, and verify network connectivity between all replicas.

2. Listener Configuration Issues

Reason: Misconfiguration of the Always On listener, including incorrect DNS settings or missing network interfaces, can prevent clients from connecting to the AG.
Solution: Verify DNS resolution for the listener, ensure all required network interfaces are configured on the listener, and test connectivity to the listener.