MariaDB run a new cluster while keeping an old cluster running

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Question :

I currently have a 5-cluster mariadb galera set up. Two of the servers are in the cloud while three of them are locally hosted.

I kinda want to start the three on premise servers to act as a separate cluster without the two in the cloud.

Note that the three servers on premise are not synced to the cluster as of now since I had to move some hosts to a different location. So I’ll have to sync the data then redo a new cluster locally.

Is it possible to just update the wsrep_cluster_name to another one and wsrep_cluster_address to not allow the other two then run galera_new_cluster for the local cluster? What is the best way to approach this?

I’m trying to minimize the downtime for the clusters and since it’s on production so I’m afraid I’ll mess this up. Thank you

Answer :

You approach looks correct.

The cluster address change is the critical aspect.

Once galera_new_cluster is run a new uuid is generated for the cluster, so once this happens, in theory the replication should recognize the write sets are from a different cluster, but lets not test that theory on production systems.

Changing wsrep_cluster_name is a good sysadmin change to prevent the ‘which server was I on?’ confustion.

Put firewall rules to block traffic between them cloud and local for added peace of mind

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