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?