RHEL 6 switched from using the old System V init script setup to using Upstart.
Upstart deprecates the /etc/inittab file, which ITDS used for configuring auto-starting on *nix platforms
The normal inittab method of auto-starting for ibmslapd/ibmdiradm does not work on RHEL 6. Here’s how to make it work
This TN show the steps how to setup the auto-start
