When ever I restart the openldap daemon at my CentOS server , I received this error :
Checking configuration files for slapd: bdb_db_open: unclean shutdown detected; attempting recovery.
bdb_db_open: Recovery skipped in read-only mode. Run manual recovery if errors are encountered.
If you issue command slapcat , you might be able to start the openldap without any error. But after you stop the openldap daemon , you start the openldap daemon again , you will receive the same error again.
Then you might think of this command : slapd_db_recover . If you use this command , you might face the same scenario.
How I solve the issue about this openldap error is issue the following command in sequence .
slapd_db_recover -h /var/lib/ldap
Then try to start your openldap daemon again , you might find it working.