Fail-over based on the directory server operational state
DPS 6.x load-balancing / fail-over can be configured to stop sending traffic to a specific directory server instance in maintenance, even when that instance is up and running. For instance, you may want to remove a directory server instance from the mesh while an import or re index is in progress.
DPS 6.x periodically checks each ds server for availability by issuing (amongst others) a search request. A directory server instance is considered unreachable when that search fails or does not return any entry. By default, the search request hits the rootDSE entry. It can be configured to hit an entry in cn=config or cn=monitor to take into account the directory server operation state.
For more info, look at dpconf properties monitoring-search-filter and monitoring-entry-dn
in the ldap data source object.