Backing Up SQL Databases on an Azure Cloud

You can run a full backup operation to back up SQL databases on an Azure cloud.

Limitations

By default, the Commvault software skips backing up Azure SQL databases with sizes larger than 2 TB. This limitation arises because very large databases have a high rate of failure due to Azure's limitations, especially when the data export operation to the Azure cloud exceeds 20 hours. For more information, see Export to a BACPAC file - Azure SQL Database and Azure SQL Managed Instance.

To override this default behavior, enter the maximum size of the Azure SQL database (in GB) that can be protected, in the nAzureSQLDBMaxSizeForExportInGB setting, for the applicable access node. For more information on configuring settings, see Adding a Setting for Servers. The backup jobs do not include any database with a size larger than this threshold.

Import/Export Service Considerations

The Azure SQL Database Import/Export service uses a limited number of compute VMs in each region to handle import and export operations.

When Commvault submits a backup task for an Azure SQL database, one of these regional compute VMs manages the export request. These VMs:

• Are hosted per region to avoid cross-region bandwidth delays and charges.

• Serve all subscriptions in that region.

• Function as a shared resource pool.

If too many requests are submitted concurrently in the same region, significant processing delays can occur. Completion times may range from seconds to several hours. Additionally:

• The Import/Export service creates a logical backup of the database.

• Completion time is influenced more by the number of database objects than by database size.

• Exporting large tables without clustered indexes can be very slow or may fail.

• Tables without clustered indexes cannot be split and exported in parallel; they must be exported in a single transaction, which slows performance.

Unresolved object references (for example, a view referencing a deleted table) can also slow export operations. If unresolved references appear in the export log, correct the database schema to improve export performance.

Procedure

1. From the navigation pane, go to Protect > Databases.

   The Overview page appears.

2. On the Instances tab, in the row for the Azure SQL database instance that you want to back up, click the action button , and then click Backup.

   The Backup options dialog box appears.

3. Under Backup level, select Full.

4. Click Submit.