How to create and manage read replicas in Azure Database for MySQL - Flexible Server by using the Azure portal

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APPLIES TO: Azure Database for MySQL - Flexible Server

In this article, you learn how to create and manage read replicas in Azure Database for MySQL flexible server using the Azure portal.

Note

If GTID is enabled on a primary server (gtid_mode = ON), newly created replicas also have GTID enabled and use GTID based replication. To learn more refer to Global transaction identifier (GTID)

Prerequisites

Create a read replica

A read replica server can be created using the following steps:

  1. Sign into the Azure portal.

  2. Select the existing Azure Database for MySQL flexible server instance that you want to use as a source. This action opens the Overview page.

  3. Select Replication from the menu, under SETTINGS.

  4. Select Add Replica.

    Screenshot of adding a replica.

  5. Enter a name for the replica server. If your region supports Availability Zones, you can select the Availability zone of your choice.

    Screenshot of adding a replica name.

  6. Enter location based on your need to create an in-region or universal cross-region read-replica.

    Screenshot of selecting a cross region.

  7. Select OK to confirm the creation of the replica.

Note

Read replicas are created with the same server configuration as the source. The replica server configuration can be changed after it has been created. The replica server is always created in the same resource group and the same subscription as the source server. Suppose you want to create a replica server for a different resource group or different subscription. In that case, you can move the replica server after creation. It is recommended that the replica server's configuration should be kept at equal or greater values than the source to ensure the replica can keep up with the source.

Once the replica server has been created, it can be viewed from the Replication page.

Screenshot of a list of replicas.

Stop replication to a replica server

Important

Stopping replication to a server is irreversible. Once replication has stopped between a source and replica, it cannot be undone. The replica server then becomes a standalone server and now supports read and write. This server cannot be made into a replica again.

To stop replication between a source and a replica server from the Azure portal, use the following steps:

  1. In the Azure portal, select your source Azure Database for MySQL flexible server instance.

  2. Select Replication from the menu, under SETTINGS.

  3. Select the replica server you wish to stop replication.

    Screenshot of a list of replicas.

  4. Select Promote. Promote action caused replication to stop and convert the replica into an independent, standalone read-writeable server.

    Screenshot of selecting promote.

  5. Confirm you want to stop replication by selecting Promote.

    Screenshot of stopping replication by selecting promote.

Delete a replica server

To delete a read replica server from the Azure portal, use the following steps:

  1. In the Azure portal, select your source Azure Database for MySQL flexible server instance.

  2. Select Replication from the menu, under SETTINGS.

  3. Select the replica server you wish to delete.

    Screenshot of deleting a selected server replica.

  4. Select Delete replica

    Screenshot of deleting a replica.

  5. Type the name of the replica and select Delete to confirm the deletion of the replica.

    Screenshot of confirmation of deleting a replica.

Delete a source server

Important

Deleting a source server stops replication to all replica servers and deletes the source server itself. Replica servers become standalone servers that now support both read and writes.

To delete a source server from the Azure portal, use the following steps:

  1. In the Azure portal, select your source Azure Database for MySQL flexible server instance.

  2. From the Overview, select Delete.

    Screenshot of deleting the source.

  3. Type the name of the source server and select Delete to confirm the deletion of the source server.

    Screenshot of deleting the source confirmed.

Monitor replication

  1. In the Azure portal, select the replica Azure Database for MySQL flexible server instance you want to monitor.

  2. Under the Monitoring section of the sidebar, select Metrics:

  3. Select Replication lag in seconds from the dropdown list of available metrics.

    Screenshot of selecting the replication lag.

  4. Select the time range you wish to view. The image below selects a 30-minute time range.

    Screenshot of selecting time range.

  5. View the replication lag for the selected time range. The image below displays the last 30 minutes.

    Screenshot of selecting time range 30 minutes.

Next steps

  • Learn more about read replicas
  • You can also monitor the replication latency by following the steps mentioned here.
  • To troubleshoot high replication latency observed in Metrics, visit the link.