LDAP Error DB_RUNRECOVERY

Sometimes LDAP server shutdown unexpectedly and after restart ldap reported the error:

DB_RUNRECOVERY: Fatal error, run database recovery

and OpenLDAP can't start.

The recovery procedure is as follows:

1. Run recovery:
   slapd_db_recover -v -h /var/lib/ldap
2. Change ownership of the ldap directory back to ldap:
chown ldap:ldap -R /var/lib/ldap
3. Start LDAP server and check its status:
   service ldap start
   service ldap status