I have been trying to figure this out the pass couple of weeks. We used to have a 5 host Percona cluster at different providers. When it started acting up I read that it is a bad idea to have synchronous replication across data centers. Now we have a 3 node cluster in one data center. I am trying to figure out the best way to have redundancy. I read that you can have 2 individual clusters, one in each data center and have an async link between them. Upon further reading though it seems that it is typically for a DR scenario so the slave cluster is not utilized and while the fail over is easy, the fall back is a bit involved. I am very new to DB clustering, I am hoping for guidance. The database clients will be using HAProxy and will only point to the hosts in one datacenter. I am hoping that I can split the clients half to each DC and have the async link replicate the data across.
Thank you very much for all your help.
