EDIT: This MDEV is irrelevant as its possible to put these parameters on the [mysqld_safe] section of my.cnf.

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If you want MariaDB to be started at init time with the --numa-interleave parameter (or any other useful parameter such as --malloc-lib) passed to mysqld_safe, you actually need to modify the init script line invoking mysqld_safe, for example on the Debian init script :

/usr/bin/mysqld_safe "${@:2}" > /dev/null 2>&1 &

Would be replaced with :

/usr/bin/mysqld_safe --numa-interleave "${@:2}" > /dev/null 2>&1 &

It could be problematic in case you would want to upgrade the init script to a newer version and dont remember or have the knowledge of the modifications or if you use a packaged version of MariaDB and the init script had been modified, you will have to either keep you modified script while not having its latest version or manually report the modifications on the new one.

A "debian-oriented" solution would be to use a package config file such as /etc/default/mariadb-server where parameters such as :

DAEMON_OPTS="--numa-interleave --sometingelse=50"

Or :

NUMA_INTERLEAVING=yes

SOMETHINGELSE=50

This way, the specific parameters would be kept upon init script upgrade and easy to find/modify.

Another universal solution could be to put a variable at the beginning of the init script that would be easier to report manually on another init script and could be kept on package upgrade.