On performing a DSM Postgres Disaster Recovery Switchover, no Replication User Connection String is availble when Demoting Primary Instance

Products

• VMware Data Services Manager

Issue/Introduction

• A Data Services Manager (DSM) disastor recovery switchover of a postgreSQL DB instance is performed, following the workflow in Performing a Disaster Recovery Switchover Using VMware Data Services Manager 
  
  
• The first operation, "Promote a Secondary PostgreSQL Instance to Primary", is completed successfully
  
  
• On applying "Demote a Primary PostgreSQL Instance", the "Copy Replication User Connection String" is grayed out (step 3). This prevents the former primary DB instance being reconfigured (on demotion) to be a replica for the newly promoted instance.  

Environment

VMware Data Services Manager 9.x

Cause

When implementing "Promote a Secondary PostgreSQL Instance to Primary", a replication slot has not been configured to be implemented on the DB instance being promoted.

Resolution

To configure a replicaton slot during the "Promote a Secondary PostgreSQL Instance to Primary" workflow, within the "Promote Database" page: 

• Expand the "Modify Promotion Configuration" section
• Toggle on "Enable Remote Replication"
• Configure a replication slot for the DB instance (to be configured when promoted)
  
  A replication user conneciton string will be generated, which then is avialable to apply in "Demote a Primary PostgreSQL Instance".
   

Alternatively, if promoting the secondary DB instance is completed without these steps, then, a replication slot for the promoted DB can be configured as follows:

• Within the DSM UI, select Databases - Postgres - <Promoted Database Instance>
• Select "Data Availability and Remote Replication" 
• Toggle on "Enable Remote Replication"
• Configure a replication slot for the DB instance