I've three servers with
Debian 9,
Maria 10.1 and running a Galera cluster.
We're upgrading the hardware by getting three new servers. They will have Debian 10 and Maria 10.3.
What are my options for accomplishing this with minimal service downtime?
One option I can think of
Using a mysqldump snapshot, set up Maria on one of the new servers to replicate as an asyncronous slave from one node of the existing cluster.
Set up Maria on the two remaining new servers in a cluster with that async slave.
When all looks good, migrate workload to the new cluster.
Does that seem reasonable?
Tom