Shutdown Question

Have a large database, including it's own internal HA configuration, that I need to ensure is stopped gracefully and this graceful database stop takes considerable time sometimes >15 mins depending on the overall transaction workload that's going on.

I have a good working service file for doing it's startup. But, what i really need is a good method to stop it cleanly.

I have tried doing a systemd service to shutdown which actually does begin to properly initiate stopping the database, but, everything shuts down around it basically taking the rug out from under it essentially crashing the database.

What's the best manner to now gracefully stop something under systemd?

Thanks