How do I enable database zone redundancy on my Azure SQL DB

Hello Darren Gourley,

Enabling zone redundancy on your Azure SQL Database in East US with a serverless tier isn't possible because the serverless compute model doesn't support it—zone redundancy requires provisioned compute to distribute replicas across availability zones, while serverless uses a dynamic, on-demand model that lacks fixed zonal placement. The "Yes" toggle is greyed out or absent in the portal due to this incompatibility; you'll need to migrate to a provisioned General Purpose or Business Critical tier to enable it. Here's a quick path forward.

Why It's Not Available

Serverless Limitations: Serverless databases (vCore or DTU) prioritize auto-scaling and pause/resume for cost savings but can't guarantee zonal redundancy, as resources aren't pinned to specific zones. East US supports zone redundancy only on provisioned tiers in zones 1-3.

Requirements Check: Your region (East US) is supported, but the compute model blocks it. No errors in setup—just a feature mismatch.

Steps to Enable Zone Redundancy

Migrate to Provisioned Tier: In the Azure portal, go to your SQL Database > Compute + storage (under Settings).

Select Configure > Change tier to General Purpose (or Business Critical for higher resilience).

  Choose **Provisioned** compute (e.g., 2 vCores), enable **Zone redundancy** toggle (now available), and apply. Downtime is minimal (~5-10 minutes for small DBs).
  
     CLI alternative: `az sql db update --resource-group <rg> --server <server> --name <db> --zone-redundant Yes --license-type BasePrice --max-size 100GB --compute-model Provisioned --family Gen5 --sku-name GP_Gen5_2 --edition GeneralPurpose`.
     
     **Verify and Test**: Post-update, check **Overview** > **Zone redundancy: Enabled**. Run a failover test via **Tasks** > **Failover** to confirm HA.
     
     **Cost Note**: Provisioned starts ~$0.50/hour (Gen5, 2 vCores); monitor via Cost Management to avoid surprises compared to serverless.
     

If you must stick with serverless, use geo-replication for redundancy instead (DB > Geo-replication > Add secondary in another region). For larger setups, consider Hyperscale if scale is key.

Best Regards,

Jerald Felix

Hi Darren Gourley,

Thank you for reaching on Microsoft Q&A!

The Basic and Standard service tiers don't support zone redundancy.

Zone redundancy is available to databases in the Business Critical, General Purpose, and Hyperscale service tiers of the vCore-based purchasing model, and only the Premium service tier of the DTU-based purchasing model.

Could you please check the following points

1. Region Support: Double-check if your current region (East US) supports zone redundancy for the service tier you are using. You can refer to the list of Azure regions that support availability zones.
2. Update Process: If you’re on a supported tier, you can enable zone redundancy via the Azure portal:
   • Navigate to your SQL database.
   • Under Settings, go to Compute + Storage.
   • Set the Would you like to make this database zone redundant? option to Yes.
   • Click Apply.
3. Limitations of Serverless: If you are on a serverless model, be aware that zone redundancy may not be configurable through the portal. You might need to consider switching to a provisioned tier if you want that feature.

Please refer the following documents for more details

• https://free.blessedness.top/en-us/azure/azure-sql/database/enable-zone-redundancy?view=azuresql&tabs=portal
• https://free.blessedness.top/en-us/azure/azure-sql/database/region-availability?view=azuresql&tabs=americas#ZR-maintenance-window-availability

I hope this helps, please let us know if you are having further queries happy to help you.

Thanks!