How to Mirror MariaDB schema into Mysql? [closed]

I find it rather worrying that you are responsible for developing software for banking transactions but don't know how to find the answers for yourself and are asking the question in the wrong way. But that's more a comment than an answer.

The relative age of the installation is at least as important as the fact that one instance is Mariadb and one is MySQL.

If they are roughly the same age, the asynchonronous replication should work. Using Galera replication really would not be appropriate in this context. However you need to ensure this doesn't conflict with any replication already in place - and if we are talking about significant volumes of financial transactions you should already have that in place to ensure availability of the service.

Alternatively you can simply run

mysqldump -h hostA srcdb | mysql -h hostB destdb

....assuming you are not using particularly esoteric functionality (most of which could be handled with a sed filter). But this copies the whole database each time.

However both approaches have a number of limitations and significant implications for your overall security. Security is usually quite high on the list of priorities for a bank - and the right solution depends on what architectures and controls are in place - which we know nothing about.

I suspect that the most appropriate strategy would be to send the updates across an asynchronous message queue with end to end acknowledgements (i.e. each transaction flagged as replicated in the source then it has been ingested at the destination database. This requires custom code.