I have had a MariaDB + Galera multi-master 3-node cluster running for several years, and prior to that Percona+Galera for ~5 years, and it's been just great. It stores lookup tables for our postfix mail server, fairly small databases and low hits, but it's great to just be able to reboot nodes for updates or migration to other VMs without having to do any of the old clustering gyrations.

I almost switched to CockroachDB in the last refresh, until I found that Postfix required Latin-1 encoding or something, and CockroachDB only supported UTF8. Postfix has more recently gotten a config option for changing that.