Friday, January 7, 2022

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


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'





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

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