为什么我的 Azure 应用服务备份无法连接到我的 Azure SQL 数据库？

Question

I am experiencing a problem configuring the backup of an SQL database using Azure.

I have web application and an associated Azure SQL database. The app connects to the DB no problem. I have pasted the connection string provided to me by the Azure UI (Home -> SQL Databases -> My SQL Database) into the connection strings section of the configuration for the App Service (Home -> App Services -> My App Service -> Configuration). I created a backup of the App Service (Home -> App Services -> My App Service -> Backups -> Configuration) and ticked my connection string to be back up my database.

After about 20 minutes, the backup fails with the error:

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 - No such host is known.)

I can connect to the database from the SQL Server Management Studio running on my laptop, and from code running on my laptop, using the server, username and password from the connection string, why can the backup not connect to the database?

Many thanks for any advice.

Answer 1

Linking the same question asked on MSDN: Azure SQL Database Backup Fails, cannot connect to the database .

Please see the Requirements and Restrictions details where this functionality is not supported, which I have listed below the applicable items that apply to your scenario:

• The Backup and Restore feature requires the App Service plan to be in the Standard tier or Premium tier. For more information about scaling your App Service plan to use a higher tier, see Scale up an app in Azure. Premium tier allows a greater number of daily back ups than Standard tier.
• You need an Azure storage account and container in the same subscription as the app that you want to back up. For more information on Azure storage accounts, see Azure storage account overview .
• Backups can be up to 10 GB of app and database content. If the backup size exceeds this limit, you get an error.
• Using a firewall enabled storage account as the destination for your backups is not supported. If a backup is configured, you will get failed backups.

If none of the above apply to you, then the issue is an IP Address issue in that you need to enable "Allow access to Azure services" in the firewall for your Azure SQL (logical) Server. Additional troubleshooting can be performed by leveraging Application Insights to capture the backup failure event and then drill into the collected log detail to see what the specific error is.