Apache Backup LDAP Repository with mod_ldap
OpenLDAP uses a blank separated list of servers. Assuming that mod_ldap is using OpenLDAP, this may work:
ldap://primary.server backup.server:389/searchstringIf that doesn't work, try including two blank separated URLs:
ldap://primary.server:389/searchstring ldap://backup.server:389/searchstringEdit: mod_authnz_ldap seems to support this officially.