Learning from Expertise #8: Why cannot move SQL database from provisioned to serverless?!

Overview:

We sometimes see customers cannot move their SQL database from provisioned compute tier to serverless while the scaling operation fails with error signature like:

Failed to scale from General Purpose: Gen5, 2 vCores, 32 GB storage, zone redundant disabled to General Purpose: Serverless, Gen5, 2 vCores, 32 GB storage, zone redundant disabled for database: <database-name>.
Error code: .
Error message: An unexpected error occured while processing the request. Tracking ID: 'xxxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxx'

Resolution:

In the beginning, you can switch to serverless compute tier only under the vCore model which provides a wide range of configuration controls and offers Hyperscale/Serverless to automatically scale your database based on your workload needs.

When the scaling operation is failing with aforementioned error, this most likely due to a serverless limitation. For instance, enabling auto-pause for a serverless database is not supported if long-term retention (LTR backups) or geo-replication is enabled.

The following features do not support auto-pausing, but do support auto-scaling:

• Geo-replication (active geo-replication and auto-failover groups).
• Long-term backup retention (LTR).
• The sync database used in SQL Data Sync. Unlike sync databases, hub and member databases support auto-pausing.
• DNS alias created for the logical server containing a serverless database.
• Elastic Jobs, when the job database is a serverless database. Databases targeted by elastic jobs support auto-pausing, and will be resumed by job connections.

In case any of these features are in-use, then auto-pausing must be disabled and the database will remain online regardless of the duration of database inactivity.

For more information regarding Serverless, you can refer to Azure SQL DB documentation: Serverless compute tier - Azure SQL Database | Microsoft Docs

I hope you find this article helpful. If you have any feedback please do not hesitate to provide it in the comment section below.

Ahmed S. Mazrouh