mysql won't run via rc.local

[benben159]

hi, i'm a newbie on this OpenBSD (version 4.7). i've built an ONMP (OpenBSD-Nginx-MySQL-PHP). i've installed MySQL (using `pkg_add mysql-server`), and i've put it on rc.local like this:

if [ X"${mysql}" == X"YES" -a -x /usr/local/bin/mysqld_safe ] ; then
su -c _mysql root -c `/usr/local/bin/mysqld_safe &` > /dev/null & echo -
n “ mysqld”
fi

it won't run (i've checked it on `ps aux` output). it'll run if i execute it manually from the console

$ sudo su -c _mysql root -c `/usr/local/bin/mysqld_safe &` > /dev/null

what should i do?