In this blog post I would like to give an overview of the most common failover scenarios and operations when using MySQL Group Replication 8.0.19 (aka GR) and Percona XtraDB Cluster 8 (PXC) (which is based on Galera), and explain how each technology handles each situation. I have created a three-node cluster with Group Replication using a single Primary and a three-node PXC, both with default settings. I am also going to use ProxySQL to interface with both clusters.
In both clusters, the name of the nodes are
mysql3. In Group
Replication the Primary node is where the writes go if we are
using single primary configuration. In PXC, I will use the same
term as well and will call the node Primary where I am sending
the writes. Just to note, in PXC there is no concept of primary