机器在openldap运行期间异常掉电或者字节kill ldap进程等，可能导致Openldap启动失败，失败信息如下：
[root@AS-1 bin]# service ldap start

[root@AS-1 bin]# service ldap start

Checking configuration files for slapd:  bdb_db_open: Warning – No DB_CONFIG file found in directory /var/lib/ldap: (2)

Expect poor performance for suffix .

bdb_db_open: Database cannot be opened, err 13. Restore from backup!

bdb(): DB_ENV->lock_id_free interface requires an environment configured for the locking subsystem

backend_startup_one: bi_db_open failed! (13)

slap_startup failed (test would succeed using the -u switch)

                                                           [FAILED]

stale lock files may be present in /var/lib/ldap           [WARNING]

修复这个问题的方法：
[root@AS-1 bin]# slapd_db_recover -v -h /var/lib/ldap/
[root@AS-1 bin]# service ldap start

这个时候ldap应该就可以正常启动了。