Charmed MySQL How-to - Async: Removal

Removal of Async replication

Pre-requisits

Make sure both Rome and Lisbon Clusters are deployed using the Async Deployment manual!

Detach Cluster from ClusterSet

Note: It is important to switchover the Primary Cluster before detaching it from ClusterSet!

Assuming the Lisbon is a current Primary and we want to detach Rome (for removal or reuse):


juju remove-relation replication-offer db2:replication

The command above will move cluster Rome into the detached state blocked keeping all the data in place.

All units in Rome will be in a standalone (non-clusterized) read-only state.

From this points, there are three options, as described in the following sections.

Rejoin detached cluster into previous ClusterSet

At this stage, the detached/blocked cluster Rome can re-join the previous ClusterSet by restoring async integration/relation:


juju switch rome

juju integrate replication-offer db1:replication

juju switch lisbon

juju run db2/leader create-replication

Removing detached cluster

Remove no-longer necessary Cluster Rome (and destroy storage if Rome data is no longer necessary):


juju remove-application db1 # --destroy-storage

New ClusterSet from detached Cluster

Convert Rome to the new Cluster/ClusterSet keeping the current data in use:


juju run -m rome db1/leader recreate-cluster