Increasing the global log level alone might not display all the log entries from the Directory Server Plugin. Editing Directory Server's cn=config entry may also be required. To enable more informational logging, set the following attributes on Directory Server's cn=config entry.
This entry can be manipulated over LDAP while Directory Server is running, or by editing the dse.ldif file when Directory Server is not running.
nsslapd-infolog-area is a bit mask entry. If it already has a value, then bit-wise OR in the 16th least significant bit into the value.
To enable additional logging, set the attributes on Directory Server's cn=config entry as follows:
nsslapd-infolog-area: 65536
nsslapd-infolog-level: 1