PostgreSQL Cluster Activation

Owned by Vijayganesh Sivaprakasam
Last updated: Aug 29, 2023 by Eric Wang
3 min read

 

1. Introduction

Activating the standby is a simple and straightforward process. This is done during true DR scenarios or for DR testing.

The configuration is reversed for true DR scenarios after activation, and the original primary should be dropped and recreated as standby.

The standby can be activated once the activity is completed for DR testing purposes. Below are the steps that need to be performed.

  1. Drop the activated standby cluster.

  2. Remove the configuration

  3. Create the configuration again.

  4. Re-create the DR cluster.

The Activation process is same across all three modes of DR methods

  1. WAL Streaming

  2. WAL Archiving

  3. WAL Shipping

Only one example is shown below.

2. Technical Explanation

  1. Database Status

    1. Standby server should be “HOT STANDBY“/”WARM STANDBY”

3. Activate Standby

  1. The standby cluster is ready for activation

  2. Option to have custom scripts that can be run on both existing primary and standby host servers.

2. Click Activate to start the activation process. This would ask for further confirmation to activate the standby cluster.

 

 

 

 

  1. Post activation the configuration status changes to “ IN FAILOVER STATE.”

  2. The original standby server is now changed to ONLINE status, and this server acts as the primary cluster server.

  3. The original primary server status is now ONLINE (Usually in a true DR scenario the status would be offline)

 

4. Recover from Failover

This procedure is used to re-create the standby cluster on the original primary.

  1. The configuration status IN FAILOVER STATE. The original standby is the new primary.

  2. The status of the original primary is down.

  3. The configuration is confirmed to be ready for recovery from failover.

  4. Click on “Recover From Failover” to start the process.

 

 

After the above process completes, log in on the server and clean up the data directory of the old primary. The option to set up the DR database will appear and click on the“Set up now?” to create the DR cluster on the original primary.