Hi, thanks for the compliments :).

MySQL group replication has some issues: It can fail your commits if multiple masters have conflicting transactions, which is a problem for cross-shard distributed transactions. Additionally, group replication is too chatty and doesn't work well cross-dc.

I actually have a counter-proposal that addresses the above concerns here: http://ssougou.blogspot.com/2016/09/distributed-durability-i....