We have a MySQL database cluster using NDB with four nodes, two in each datacenter.

The database uptime is very important, it must be up 24x7 and we cannot affort downtime.

Is the following a good idea:

  • Have another MySQL running that is a replica of the main database
  • When the cluster fails, have the load balancer switch over to the replica MySQL
  • Once the cluster is back up again, switch back to the cluster database

Can you give me advantages and disadvantages of such a setup?


  • So, you want a single instance to serve as a disaster recovery mechanism for an existing cluster that presumably already has the DR capability (otherwise why would you span two datacentres)? Can a single instance sustain the workload normally distributed across four nodes?
    – mustaccio
    Mar 9, 2023 at 20:30


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