Right now Aurora only allows a single master, with up to 15 read-only replicas.
We love testing failure scenarios, however our options for such tests with Aurora are limited (we might get back to that later). Anyhow, we told the system, through the RDS Aurora dashboard, to do a failover. These were our observations:
Role Change Method
Both master and replica instances are actually restarted (the MySQL uptime resets to 0).
This is quite unusual these days, we can do a fully controlled role change in classic asynchronous replication without a restart (CHANGE MASTER TO …), and Galera doesn’t have read/write roles as such (all instances are technically writers) so it doesn’t need role changes at all.
Failover between running instances takes about 30 seconds. This is in line with information provided in the …[Read more]