on-premises SQL Server to an SQL Server in an Azure VM

Migrating an on-premises SQL Server to an SQL Server in an Azure VM involves careful planning and execution. Here is a detailed strategy to help you migrate your SQL Server, considering both Azure VM and Azure SQL Managed Instance options.

1. Assessment and Planning

1.1 Assess the Current Environment

• Inventory all SQL Server instances, databases, and their sizes.

• Evaluate the SQL Server version and edition.

• Identify dependencies and connected applications.

• Check for unsupported features in Azure.

1.2 Choose the Migration Approach

• Azure VM: Lift-and-shift approach, where you move your SQL Server to a virtual machine in Azure.

• Azure SQL Managed Instance: Modernized approach, leveraging managed services with high compatibility for on-premises SQL Server.

1.3 Evaluate Connectivity Options

• Determine the best connectivity option for your scenario (VPN, ExpressRoute).

1.4 Sizing and Cost Estimation

• Estimate the required size of Azure VM or Managed Instance based on current usage.

• Calculate the cost of the chosen Azure services.

2. Preparation

2.1 Prepare the Azure Environment

• Set up your Azure account and create a resource group.

• Create a Virtual Network (VNet) and subnet for your Azure VM or Managed Instance.

• Configure network security groups (NSGs) to control traffic.

2.2 Provision Azure SQL Server

• For Azure VM: Provision a VM with the appropriate size and SQL Server installed.

• For Managed Instance: Create a Managed Instance within your VNet.

3. Database Backup and Restore

3.1 Backup On-Premises Databases

Perform full database backups of your on-premises SQL Server databases.
sql
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BACKUP DATABASE [YourDatabaseName] TO DISK = 'C:\Backup\YourDatabaseName.bak' WITH INIT;

3.2 Transfer Backups to Azure

• Use Azure Storage to transfer backups:

Upload backups to an Azure Blob Storage container using tools like AzCopy or Azure Storage Explorer.
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azcopy copy 'C:\Backup\YourDatabaseName.bak' 'https://<yourstorageaccount>.blob.core.windows.net/<yourcontainer>/<yourblob>'

4. Migration Execution

4.1 Restore Backups to Azure SQL Server

• For Azure VM:

  1. Connect to the Azure VM using Remote Desktop Protocol (RDP).

  2. Transfer backups from Azure Blob Storage to the Azure VM.

  3. Restore the backups on the SQL Server instance in the Azure VM.

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RESTORE DATABASE [YourDatabaseName] FROM DISK = 'D:\Backup\YourDatabaseName.bak' WITH MOVE 'YourDatabaseName' TO 'D:\SQLData\YourDatabaseName.mdf', MOVE 'YourDatabaseName_log' TO 'D:\SQLLogs\YourDatabaseName_log.ldf';

• For Azure SQL Managed Instance:

  1. Use the URL of the backup file in Azure Blob Storage to restore the database directly.

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RESTORE DATABASE [YourDatabaseName] FROM URL = 'https://<yourstorageaccount>.blob.core.windows.net/<yourcontainer>/<yourblob>.bak' WITH MOVE 'YourDatabaseName' TO '<path_to_data_file>', MOVE 'YourDatabaseName_log' TO '<path_to_log_file>';

5. Post-Migration Steps

5.1 Validation

• Verify the integrity and completeness of the data.

• Run application tests to ensure all dependencies are functioning correctly.

5.2 Performance Tuning

• Check and adjust performance parameters for the new environment.

• Monitor and optimize query performance.

5.3 Update Connection Strings

• Update application connection strings to point to the new SQL Server in Azure.

  • Ensure security best practices, such as encryption and secure credentials, are followed.

6. Cutover and Go-Live

6.1 Plan Downtime

• Schedule a maintenance window for the final cutover.

• Inform all stakeholders about the migration timeline and expected downtime.

6.2 Final Data Synchronization

• Perform differential backups and restores or use transactional replication to synchronize any changes made during the migration period.

6.3 Switch Over

• Redirect traffic to the new SQL Server in Azure.

• Monitor the system closely for any issues post-migration.

7. Decommissioning

7.1 Decommission On-Premises SQL Server

• After successful migration and testing, decommission the on-premises SQL Server.

• Ensure data is backed up and securely archived if necessary.

8. Continuous Monitoring and Optimization

8.1 Monitoring

• Set up Azure Monitor and other monitoring tools to keep an eye on performance, availability, and security.

8.2 Regular Maintenance

• Regularly review performance metrics.

• Apply updates and patches to the Azure VM or Managed Instance as needed.

By following this detailed strategy, you can ensure a smooth migration of your on-premises SQL Server to an SQL Server in an Azure VM or Managed Instance. Each step should be carefully planned and executed to minimize downtime and ensure data integrity.