Hi Quanah,
Thank you for your answer.
My boss has asked me for a tutorial due our new installation that we'll do. Then we'll update our production environment to latest version of distribution and openldap.
I've used, in my test, hdb backend because I've used default installation from yum package management. Then I'll change it to mdb in my tutorial and new installation. (I've seen, after you explanation, that OpenLDAP documentation says hdb is deprecated.)
About "olcBackend", I've understand, after your explanation, that is normal it there isn't in CentOS.
Best regards and thank you so much,
--
Igor Sousa