Connection time out issue in Manged vnet IR from ADF to SQL. How to resolve?

Question

We are using Managed Vnet integration runtime to connect between Azure data factory and SQL DB. This was suggested by microsoft since our Azure SQL is private only, and Autoresolve IR wont work. We tried with SHIR earlier, but since we are using dataflows in ADF and shir doesn't support it we cannot use it.

When using Managed vnet IR, the connectivity works initially, but when running the adf pipelines we are seeing errors intermittently:

ErrorCode=SqlFailedToConnect,'Type=Microsoft.DataTransfer.Common.Shared.HybridDeliveryException,Message=Cannot connect to SQL Database. Please contact SQL server team for further support. Server: 'example.database.windows.net', Database: 'dbname', User: ''. Check the linked service configuration is correct, and make sure the SQL Database firewall allows the integration runtime to access.,Source=Microsoft.DataTransfer.Connectors.MSSQL,''Type=Microsoft.Data.SqlClient.SqlException,Message=A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: TCP Provider, error: 0 - The wait operation timed out.),Source=Framework Microsoft SqlClient Data Provider,''Type=System.ComponentModel.Win32Exception,Message=The wait operation timed out,Source=,'

We have enabled managed private endpoint to sql from ADF, and the test connection works fine. Also we are seeing this intermittently only. Could you please suggest a resolution for this as it is affecting our production.

Answer 1

Hello @Jerald K Philip

This error message indicates that the connection to the SQL server is timing out. There could be several reasons for this issue, such as network latency, firewall rules, or resource constraints.

Here are some steps you can take to troubleshoot and resolve the issue:

1. Check the network connectivity between the Azure Data Factory and SQL DB. You can use tools like ping or tracert to check the network latency and identify any network issues.
2. Check the firewall rules on the SQL server. Make sure that the firewall rules allow the Managed VNet IR to access the SQL server. You can also try temporarily disabling the firewall to see if it resolves the issue.
3. Check the resource constraints on the SQL server. Make sure that the SQL server has enough resources to handle the workload. You can also try scaling up the SQL server to see if it resolves the issue.
4. Check the configuration of the Linked Service in Azure Data Factory. Make sure that the Linked Service is configured correctly and that the credentials are valid.
5. Check the logs in Azure Data Factory to see if there are any errors or warnings related to the Managed VNet IR or the SQL server. If none of these steps resolve the issue, you may need to contact Microsoft support for further assistance.

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