deploy monitor backend while existing DB in the root namespace

[GALAMBOS Daniel <dancsa@dancsa.hu>]

Hi,

My task was to configure our existing openldap (debian wheezy
2.4.31-1+nmu2) to use use monitor backend. The main problem is that our
(BDB backed) database has empty suffix (for historical reason).

If the monitor defined later under the /etc/ldap/slapd.d then the BDB,
slapd fails to start, because BDB database would hide the monitor. 

database init failed (monitor)
52b038c0 olcDatabase: value #0: "monitor" database serving namingContext
"cn=Monitor" is hidden by "bdb" database serving namingContext "".
 (monitor)
52b038c0 config error processing olcDatabase={2}monitor,cn=config:
"monitor" database serving namingContext "cn=Monitor" is hidden by "bdb"
database serving namingContext "".

If it's defined before the bdb, then the slapd starts, but ldapsearch
give 'no such object' for cn=Monitor.  (should not be permission issue)
It was doesn't matter if i included 'olcSubordinate: true' in the
monitor.  When I added a non-empty suffix to the bdb in the devel
environment, the monitor worked, but this can't be the solution for our
prod servers.

monitor backend is defined by:

dn: olcDatabase=monitor
objectClass: olcDatabaseConfig
olcDatabase: monitor
olcAccess: {0}to * by read
olcSubordinate: TRUE


A colleague is concerned about the performance loss because of the
monitor backend. Does monitor use significant resources in a heavily
used slapd?


Thanks,
Dancsa