I have 2 masters and 1 slave (replicating form both masters).
M1- MariaDB 10.4.11
M2- MariaDB 10.4.16
S1- MariaDB 10.4.12
I want to upgrade this LIVE system to 10.5 with possibly 0 downtime. The idea is this:
- upgrade slave S1 (this is used mainly for backups, not queried at all)
- switch all traffic to M2, stop M1 and upgrade M1
- turn on M1 and sync it from M2 – at this stage I will have active master M2 running old 10.4 MariaDB, but both standby master M1 and slave S1 are already on 10.5
- switch all traffic to M1, stop M2 and upgrade M2
- sync M2 from M1 and keep it as standby master
I guess my main question is – Is MariaDB 10.5 <-> 10.4 replication compatible? Any particular issues I should look for?
Thanks!
Best Answer
A MariaDB replica can replicate from an older master. The other way around won't work.
You should add a step 2.5: stop replicating from M1 to M2 (even if it's just a standby master). After step 4, M1 can replicate from M2 again.