Can an innodb cluster continue to run while one at a time replacing each server with Percona? I presume being a drop-in replacement that percona is able to do innodb clustering after the migration is completed?
What should I know about converting it to an XtraDB Cluster afterwards?
Are you using MySQL Group Replication currently? From what I understand, you plan to first replace the MySQL binaries to equivalent Percona Server binaries? If so, yes, that should work and a PS node should work fine together with vanilla MySQL nodes in one Group Replication cluster. However, such setup is not well tested solution I am afraid, so best to test such migration prior trying on production.
When it comes to PXC (and Galera replicaiton) - that’s completely different solution and there is no simple in-place migration path from GR to PXC. In that case, I would suggest creating new PXC cluster, import data from existing InnoDB Cluster (GR) to it, and start async replication from one to another first.
Yes, I think you’ve got the picture. There’s currently a GR setup that would likely be one-at-a-time replaced with their equivalent Percona server binaries. and then attempt to migrate the GR cluster over to a PXC cluster… but if it’s a better plan to start replicating the GR cluster over to a PXC cluster am I actually gaining anything by upgrading it to Percona first or just creating extra work and a possibility of extra headaches for myself with an unnecessary step?
Do the Percona binaries have innodb cluster improvements in stability/durability over the Mysql release?