Promoting a Read Replica to Primary

Scenarios

RDS enables you to promote a read replica to a single-node DB instance. When you promote a read replica, replication is stopped. After the promotion is complete, the read replica is available as a single DB instance. This operation does not affect the performance of the original DB instance.

If your DB instance fails and you want to quickly obtain a readable and writable instance, you can promote one of the instance's read replicas to primary.

Constraints

• This function is available only to RDS for MySQL 5.7 and 8.0.
• Only pay-per-use read replicas can be changed to single DB instances.
• This function is unavailable for DB instances with proxy enabled.
• Only general-purpose and Kunpeng general-enhanced read replicas using cloud SSDs can be promoted to single DB instances.

Procedure

1. Log in to the management console.
2. Click in the upper left corner and select a region.
3. Click in the upper left corner of the page and choose Databases > Relational Database Service.
4. On the Instances page, locate the target RDS for MySQL instance and click in front of it to expand the read replica list.
5. Find the desired read replica and choose More > Promote to Primary in the Operation column.
   Figure 1 Locating a read replica
   

6. In the displayed dialog box, click Yes.
   Figure 2 Promoting a read replica to primary
   

7. After the promotion is complete, check and manage the new instance on the Instances page.
   • During the promotion, the read replica status is Promoting to primary. Upon the completion of the promotion, a full backup is automatically performed.
   • After the read replica is promoted to primary, it is disassociated from the original DB instance. Its Status becomes Available and DB Instance Type becomes Single.
   • The billing mode on the new instance remains unchanged.