List the types of DB supported by openldap?

Below list of DBs are supported by openldap

bdb

Berkeley DB instance definition. This is the recommended database back-end type. It uses the Sleepycat Berkeley DB to store data.

ldbm

LDAP DBM type. Easy to configure, but not as durable as the bdb database back-end type. It also uses Berkeley DB, GNU DBM, and MDBM to store data.

sql

Uses a SQL database back-end to store data.

ldap

Used as a proxy to forward incoming requests to another LDAP server.

meta

Metadirectory database back-end. It is an improvement on the LDAP-type back-end. It performs LDAP proxying with respect to a set of remote LDAP servers.

monitor

Stores information about the status of the slapd daemon.

null

Operations to this database type succeed, but do nothing. This is the equivalent of sending stuff to /dev/null in Linux/UNIX.

passwd

Uses the system’s plain-text /etc/passwd file to serve user account information.

tcl

An experimental back-end that uses a Tcl interpreter that is embedded directly into slapd.

perl

Uses a Perl interpreter that is embedded directly into slapd.