MariaDB: recommended upgrade procedure for minimal downtime
Explain not just how to avoid one issue, but in general how to avoid almost all typical issues by first ensuring a clean shutdown takes place.
Recommended steps proven to work in https://salsa.debian.org/mariadb-team/mariadb-server/-/pipelines/536587. More details in https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1035949#120.