I’ve recently worked with customers using replication rings with 4+ servers; several servers accepting writes. The idea behind this design is always the same: by having multiple servers, you get high availability and by having multiple writer nodes, you get write scalability. Alas, this is simply not true. Here is why.
Having several servers is a necessary condition to have high availability, but it’s far from sufficient. What happens if for instance C suddenly disappears?
- The replication