> In terms of relational databases, Galera Cluster’s group replication is also imperfect, but closer to the ideal.
As a longtime Galera user, I have to admit this "closer to the ideal" has nothing in common with reality. It fails, it loses data, quorum kills healthy nodes, transactions add significant latency. The more nodes you have, the lower performance and fault tolerance. One mysql node could literally endure triple of load, which could be deadly for Galera cluster of 3 nodes. Also, it rollbacks transactions silently.
As a longtime Galera user, I have to admit this "closer to the ideal" has nothing in common with reality. It fails, it loses data, quorum kills healthy nodes, transactions add significant latency. The more nodes you have, the lower performance and fault tolerance. One mysql node could literally endure triple of load, which could be deadly for Galera cluster of 3 nodes. Also, it rollbacks transactions silently.