ok thanks
I found that in the mailing list archive, dating back from 2007 (http://www.openldap.org/lists/openldap-software/200708/msg00015.html)
Indeed back-sql was intended to loosely support acting as a syncrepl provider (limited to refreshOnly), but it's currently broken, and it's never been fixed (mostly due to lack of interest). Patches (or sponsorships) are welcome. Ing. Pierangelo Masarati OpenLDAP Core Team
So I was wondering if it has been fix since...
your question is, can I use back-sql as syncperov. A sql backend is not a fully featered database to use with slapd.
-Dieter