Configure high availability for Azure Database for PostgreSQL flexible server

This article describes how to enable or disable high availability (HA) on your Azure Database for PostgreSQL flexible server. The information applies whether you're using servers in the same zone or using a zone-redundant deployment model. This article describes how to enable or disable high availability (HA) on your Azure Database for PostgreSQL flexible server. The information applies whether you're using servers in the same zone or using a zone-redundant deployment model.

The high-availability feature deploys physically separate primary and standby replicas. You can provision the replicas within the same availability zone or in different zones, depending on the deployment model that you choose. For more information, see the article about high-availability concepts. You can enable high availability during or after the creation of your Azure Database for PostgreSQL flexible server. The high-availability feature deploys physically separate primary and standby replicas. You can provision the replicas within the same availability zone or in different zones, depending on the deployment model that you choose. For more information, see the article about high-availability concepts. You can enable high availability during or after the creation of your Azure Database for PostgreSQL flexible server.

Enable high availability for existing servers

You can enable high availability on an existing Azure Database for PostgreSQL flexible server at any time. When you enable high availability, the service creates a standby replica that mirrors your primary server. Depending on regional capacity and your configuration choices, the standby can be deployed in a different availability zone for maximum protection or in the same zone as the primary. You can enable high availability on an existing Azure Database for PostgreSQL flexible server at any time. When you enable high availability, the service creates a standby replica that mirrors your primary server. Depending on regional capacity and your configuration choices, the standby can be deployed in a different availability zone for maximum protection or in the same zone as the primary.

Portal
CLI

Using the Azure portal:

Select your Azure Database for PostgreSQL flexible server. Using the Azure portal:
Select your Azure Database for PostgreSQL flexible server.
In the resource menu, under the Settings section, select High availability.

The Zonal resiliency option controls whether your server is protected across availability zones. You have two choices:

Disabled (99.9% SLA): High availability isn't configured.
Enabled (99.99% SLA): When you select this option, Azure tries to create the standby server in a different availability zone than the primary. This option gives you the best protection against zone-level failures.

If you enable zonal resiliency but your region lacks capacity for a zone redundant setup, an extra checkbox appears under the Enabled (99.99% SLA) option. Select this checkbox to allow the standby server to be created in the same zone as the primary server. When zonal capacity becomes available, Azure automatically migrates your workloads from same zone to zone redundant.

If you didn't enable zonal resiliency, select the Enabled option.
When you select the Enabled option, the Zone redundant option is applied by default for regions that support availability zones. This configuration protects against zonal failures.
If the region doesn't have zonal capacity, to make sure that high availability (HA) gets enabled in your preferred region, select the checkbox under the enabled option to allow creating HA with Same-Zone mode of the region:
When you're done configuring the settings, select Save to apply the changes.
A dialog shows the cost increase associated with the deployment of the standby server. If you decide to proceed, select Enable high availability.
A new deployment is launched to enable high availability on your Azure Database for PostgreSQL flexible server.
When the deployment completes, you can select Go to resource to go back to your Azure Database for PostgreSQL flexible server.

Use the az postgres flexible-server update command to enable high availability in an existing server.

To enable high availability with the standby server in the same zone as the primary server, use this command:

az postgres flexible-server update \
  --resource-group <resource_group> \
  --name <server> \
  --high-availability SameZone

To enable high availability with the standby server in a different zone from the primary server's zone, and if you want the zone to be automatically selected, use this command:

az postgres flexible-server update \
  --resource-group <resource_group> \
  --name <server> \
  --high-availability ZoneRedundant

Optionally, you can select the availability zone in which to deploy the standby server. Use this command:

az postgres flexible-server update \
  --resource-group <resource_group> \
  --name <server> \
  --high-availability ZoneRedundant \
  --standby-zone <standby_zone>

If you enable high availability with zone redundancy, and the zone you specify for standby matches the zone of the primary, you get this error:

Your server is in availability zone <server>. The zone of the server cannot be same as the standby zone.

If you enable high availability with zone redundancy, and the zone you specify for standby isn't available in that region, you get this error:

Code: InvalidParameterValue
Message: Invalid value given for parameter StandbyAvailabilityZone,availabilityZone. Specify a valid parameter value.

If you enable high availability with zone redundancy, and the region doesn't have multiple availability zones, you get this error:

This region is single availability zone. Zone redundant high availability is not supported in a single availability zone region.

If you enable high availability in one mode, and then try to enable it again by specifying a different mode, you get this error:

Code: InvalidParameterValue
Message: Invalid value given for parameter Cannot switch Properties.HighAvailability.Mode directly from SameZone to ZoneRedundant. Please disable HA and then enable HA.. Specify a valid parameter value.

The --zonal-resiliency parameter helps you create a standby server in a different availability zone than primary and protects against zone-level failures. It accepts two values:

Enabled: When you select this option, Azure tries to create the standby server in a different availability zone than the primary. This option gives you the best protection against zone-level failures.
Disabled: High availability isn't configured.

To ensure your server is configured for high availability, enable the --allow-same-zone parameter. In regions without multiple availability zones, this option allows the standby server to be created in the same zone as the primary. When zonal capacity becomes available, Azure automatically migrates your workloads from same-zone HA to zone-redundant HA.

az postgres flexible-server update \
  --resource-group <resource_group> \
  --name <server> \
  --zonal-resiliency enabled
  --allow-same-zone

Disable high availability

You can disable high availability on your Azure Database for PostgreSQL flexible server when you no longer need the protection of a standby replica. Disabling high availability removes the standby server and reduces costs, but your server is no longer protected against zone or server failures.

Portal
CLI

Using the Azure portal:

Select your Azure Database for PostgreSQL flexible server.
In the resource menu, under the Settings section, select High availability.
If high availability is enabled, the Enabled radio button for Zonal Resiliency is already selected. Also, High availability mode is set to the configured mode, and the High availability status value is typically Healthy.
Select the Disabled radio button to disable high availability.
Select Save to apply the changes.
A dialog shows the cost reduction associated with the removal of the standby server. If you decide to proceed, select Disable high availability.
A deployment starts. When it finishes, a notification shows that you successfully disabled high availability.

Use the az postgres flexible-server update command to disable high availability in an existing server.

az postgres flexible-server update \
  --resource-group <resource_group> \
  --name <server> \
  --zone-resiliency Disabled

Enable Business Critical (High Availability) during server provisioning

You can configure high availability when you first create your Azure Database for PostgreSQL flexible server. By enabling high availability during provisioning, you deploy a standby replica alongside your primary server, so you get immediate protection against zone or server failures.

Portal
CLI

Using the Azure portal:

During provisioning of a new Azure Database for PostgreSQL flexible server, go to the Business Critical (High availability) section. Select Enabled option in the Zonal resiliency section.
- By default, the server tries to create the standby server in a different availability zone with Zone-Redundant HA mode for maximum zonal resiliency.
- If zonal capacity isn't available, select the Allow standby in same zone if zonal resiliency fails checkbox as a fallback. If you don't select this option, you can't proceed to the next step in the create workflow. This check ensures high availability remains enabled. When zonal capacity becomes available, Azure automatically migrates your workloads from Same-Zone HA to Zone-redundant HA.
- After you select the checkbox, proceed to the Authentication section in the create workflow.
Select a specific zone for the primary server by setting Availability zone to any value other than No preference.

Use the az postgres flexible-server create command to enable high availability while provisioning a new server.

Note

Complete the following commands with parameters and values that vary, depending on how you want to configure other features of the provisioned server.

To deploy the primary server with a standby server in the same zone, and let the service choose the zone for you, use this command:

az postgres flexible-server create \
  --resource-group <resource_group> \
  --name <server> \
  --zone-resiliency Enabled
  --allow-same-zone ...

To deploy the primary server with a standby server in the same zone, and explicitly choose the zone, use this command:

az postgres flexible-server create \
  --resource-group <resource_group> \
  --name <server> \
  --zone-resiliency Enabled \
  --zone <zone> ...

If the specified availability zone isn't supported in the selected region, you get this error:

Code: AvailabilityZoneNotAvailable
Message: Specified availability zone is not supported in this region. Please choose a different availability zone.

To deploy the primary server with a standby server in a different zone, and let the service choose both zones for you, use this command:

az postgres flexible-server create \
  --resource-group <resource_group> \
  --name <server> \
  --zone-resiliency Enabled ...

To deploy the primary server with a standby server in a different zone, and to specify the zone for the primary but let the service choose the zone for the standby, use this command:

az postgres flexible-server create \
  --resource-group <resource_group> \
  --name <server> \
  --zone-resiliency Enabled \
  --zone <zone> ...

To deploy the primary server with a standby server in a different zone, and to specify the zone for the primary and the standby, use this command:

az postgres flexible-server create \
  --resource-group <resource_group> \
  --name <server> \
  --zone-resiliency Enabled \
  --zone <zone> \
  --standby-zone <standby_zone>...

If you choose zone-redundant high availability, and specify the same value for the zones of the primary and standby servers, you get this error:

Your server is in availability zone <zone>. The zone of the server cannot be same as the standby zone.

If the high-availability mode that you select is zone redundant, and the region doesn't have multiple availability zones, you get this error:

This region is single availability zone. Zone redundant high availability is not supported in a single availability zone region.

Use the --zonal-resiliency parameter when creating an Azure Database for PostgreSQL flexible server. This parameter ensures the standby server is provisioned in a different availability zone than the primary, which improves protection against zone‑level failures.

If the region doesn't currently support multiple availability zones, add the --allow-same-zone parameter. This parameter acts as a fallback: if Azure can't create the standby in another zone, it creates the standby in the same zone as the primary so that high availability is still enabled in your chosen region. When zonal capacity later becomes available, Azure automatically migrates your workloads from same-zone HA to zone-redundant HA.

The --zonal-resiliency parameter accepts these values:

Enabled: When you select this option, Azure tries to create the standby server in a different availability zone than the primary. This option gives you the best protection against zone-level failures.
Disabled: High availability isn't configured.

az postgres flexible-server create \
  --resource-group <resource_group> \
  --name <server> \
  --zonal-resiliency enabled \
  --allow-same-zone

Initiate a forced failover

Follow these steps to force a failover of your primary server to the standby server in Azure Database for PostgreSQL.

When you initiate a forced failover, the primary server immediately goes down and triggers a failover to the standby server. Initiating a forced failover is useful when you want to test how a failover caused by an unplanned outage affects your workload.

Important

Don't perform immediate, back-to-back failovers. Wait for at least 15 to 20 minutes between failovers. This wait time allows the new standby server to be fully established.
The overall end-to-end operation time, as reported on the portal, might be longer than the actual downtime that the application experiences. You should measure the downtime from the application's perspective.

Portal
CLI

Using the Azure portal:

Select your Azure Database for PostgreSQL flexible server that has high availability enabled.
In the resource menu, under the Settings section, select High availability.
If the primary and standby servers are deployed in different zones, note the values assigned to Primary availability zone and Standby availability zone. These values reverse after the failover operation finishes.
Select Forced failover to start the manual failover procedure. A dialog informs you of the expected downtime until the failover finishes. If you decide to proceed, select Initiate forced failover.
A notification appears and mentions that a failover is in progress.
After the failover to the standby server completes, a notification informs you of the completion.
If the primary and standby servers are deployed in different zones, confirm that the values of Primary availability zone and Standby availability zone are reversed, compared to how they were before failover started.

Use the az postgres flexible-server restart command to start a forced failover.

To initiate a forced failover, use this command:

az postgres flexible-server restart \
  --resource-group <resource_group> \
  --name <server> \
  --failover Forced

If you try to force the failover of an Azure Database for PostgreSQL flexible server that doesn't have high availability enabled, you get this error:

Failing over can only be triggered for zone redundant or same zone servers.

If you try to force the failover of an Azure Database for PostgreSQL flexible server that has high availability enabled but isn't ready to initiate the failover operation, you get this error:

Code: OperationFailed
Message: Operation HandleWalServiceFailureManagementOperation failed, because server <server> not in active state.

Initiate a planned failover

Follow these steps to perform a planned failover from your primary server to the standby server in Azure Database for PostgreSQL. When you initiate this operation, it prepares the standby server and then performs the failover.

This failover operation provides the least downtime, because it performs a graceful failover to the standby server. It's useful for situations like bringing the primary server back to your preferred availability zone after an unexpected failover.

Important

Don't perform immediate, back-to-back failovers. Wait for at least 15 to 20 minutes between failovers. This wait time allows the new standby server to be fully established.
Perform planned failovers during low-activity periods.
The overall end-to-end operation time, as reported on the portal, might be longer than the actual downtime that the application experiences. You should measure the downtime from the application's perspective.

Portal
CLI

Using the Azure portal:

Select your Azure Database for PostgreSQL flexible server that has high availability enabled.
In the resource menu, under the Settings section, select High availability.
If the primary and standby servers are deployed in different zones, note the values assigned to Primary availability zone and Standby availability zone. These values reverse after the failover operation finishes.
Select Planned failover to start the manual failover procedure. A dialog informs you of the expected downtime until the failover finishes. If you decide to proceed, select Initiate planned failover.
A notification appears and mentions that failover is in progress.
After the failover to the standby server completes, a notification informs you of the completion.
If the high-availability mode is configured as Zone redundant, confirm that the values of Primary availability zone and Standby availability zone are now reversed.

Use the az postgres flexible-server restart command to start a planned failover.

To start a planned failover, use the following command:

az postgres flexible-server restart \
  --resource-group <resource_group> \
  --name <server> \
  --failover Planned

If you try to start the planned failover of an Azure Database for PostgreSQL flexible server that doesn't have high availability enabled, you get the following error:

Failing over can only be triggered for zone redundant or same zone servers.

If you try to start the planned failover of an Azure Database for PostgreSQL flexible server that has high availability enabled but isn't ready for the failover operation, you get the following error:

Code: OperationFailed
Message: Operation HandleWalServiceFailureManagementOperation failed, because server <server> not in active state.

Limitations and considerations

When you enable or disable high availability on an Azure Database for PostgreSQL flexible server, the service doesn't change other settings. These settings include networking configuration, firewall settings, parameters, and backup retention. Enabling or disabling high availability is an online operation. This operation doesn't affect your application connectivity and operations.
Azure Database for PostgreSQL supports high availability with both replicas deployed in the same zone. You can use this configuration in all supported regions. However, high availability with zone redundancy is available only in certain regions.
The Burstable tier doesn't support high availability. Only the General purpose and Memory optimized tiers support high availability.
If you deploy a server in a region that consists of a single availability zone, you can enable high availability in the same-zone mode only. If Microsoft enhances the region in the future with multiple availability zones, you can deploy new Azure Database for PostgreSQL flexible servers with high availability configured as same zone or zone redundant.

However, you can't directly enable high availability in zone-redundant mode for any server that you deployed in the region when the region consisted of a single availability zone. As a workaround, you can use the restore option or read replica option:

Restore option

Restore to latest restore point.
After you create the new server, enable high availability with zone redundancy.
After data verification, you can optionally delete the old server.
Make sure that you modify the connection strings of your clients to point to your newly restored server.

Read replica option

Create a read replica in the same region as your primary server.
Promote the read replica to become the new primary server.
To preserve the original name, either use virtual endpoints or drop the old primary, then create and promote a new read replica.
For portal users, enable Zonal Resiliency. For developer tools, set High Availability with the Zone-Redundant option.
Create a read replica in the same region as your primary server.
Promote the read replica to become the new primary server.
To preserve the original name, either use virtual endpoints or drop the old primary, then create and promote a new read replica.
For portal users, enable Zonal Resiliency. For developer tools, set High Availability with the Zone-Redundant option.

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Last updated on 2026-07-01

Configure high availability for Azure Database for PostgreSQL flexible server

Enable high availability for existing servers

Disable high availability

Enable Business Critical (High Availability) during server provisioning

Initiate a forced failover

Initiate a planned failover

Limitations and considerations

Restore option

Read replica option

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