SLAPD.BACKENDS(5)                      File Formats Manual                      SLAPD.BACKENDS(5)



NAME
       slapd.backends - backends for slapd, the stand-alone LDAP daemon

DESCRIPTION
       The  slapd(8)  daemon  can  use a variety of different backends for serving LDAP requests.
       Backends may be compiled statically into slapd, or when module support  is  enabled,  they
       may  be  dynamically  loaded.  Multiple instances of a backend can be configured, to serve
       separate databases from the same slapd server.


       Configuration options for each backend are  documented  separately  in  the  corresponding
       slapd-<backend>(5) manual pages.

       bdb    This  was  the  recommended  primary backend through OpenLDAP 2.3, but it has since
              been superseded by the hdb backend.  It takes care to configure  it  properly.   It
              uses  the  transactional database interface of the Oracle Berkeley DB (BDB) package
              to store data.

       config This backend is used to manage the configuration  of  slapd  at  run-time.   Unlike
              other  backends,  only  a  single instance of the config backend may be defined. It
              also instantiates itself automatically, so it is always present even if not explic‐
              itly defined in the slapd.conf(5) file.

       dnssrv This  backend  is  experimental.   It  serves  up referrals based upon SRV resource
              records held in the Domain Name System.

       hdb    This is the recommended primary backend for a normal  slapd  database.   hdb  is  a
              variant  of  the bdb backend that uses a hierarchical database layout.  This layout
              stores entry DNs more efficiently than  the  bdb  backend,  using  less  space  and
              requiring  less  work  to create, delete, and rename entries. It is also one of the
              few backends to support subtree renames.

       ldap   This backend acts as a proxy to forward incoming requests to another LDAP server.

       ldif   This database uses the filesystem to build the  tree  structure  of  the  database,
              using  plain ascii files to store data.  Its usage should be limited to very simple
              databases, where performance is not a requirement. This backend also supports  sub‐
              tree renames.

       mdb    This  will  soon be the recommended primary backend, superseding hdb.  This backend
              uses OpenLDAP's own MDB transactional database library. It is extremely compact and
              extremely  efficient, delivering much higher performance than the Berkeley DB back‐
              ends while using significantly less memory.  Also, unlike Berkeley DB, MDB is crash
              proof,  and  requires no special tuning or maintenance.  This backend also supports
              subtree renames.

       meta   This backend performs basic LDAP proxying with respect to  a  set  of  remote  LDAP
              servers. It is an enhancement of the ldap backend.

       monitor
              This  backend  provides  information  about the running status of the slapd daemon.
              Only a single instance of the monitor backend may be defined.

       ndb    This backend is experimental.  It uses the transactional database interface of  the
              MySQL  Cluster  Engine (NDB) to store data. Note that Oracle, which now owns MySQL,
              has withdrawn support for NDB and this backend is unlikely to be developed any fur‐
              ther.

       null   Operations in this backend succeed but do nothing.

       passwd This  backend  is  provided  for  demonstration  purposes  only.  It serves up user
              account information from the system passwd(5) file.

       perl   This backend embeds a perl(1) interpreter into slapd.  It runs Perl subroutines  to
              implement LDAP operations.

       relay  This  backend is experimental.  It redirects LDAP operations to another database in
              the same server, based on the naming context of the request.  Its use requires  the
              rwm  overlay  (see  slapo-rwm(5)  for details) to rewrite the naming context of the
              request.  It is primarily intended to implement virtual  views  on  databases  that
              actually store data.

       shell  This  backend  executes external programs to implement LDAP operations.  It is pri‐
              marily intended to be used in prototypes.

       sql    This backend is experimental.  It services LDAP requests from an SQL database.

FILES
       /etc/ldap/slapd.conf
              default slapd configuration file

       /etc/ldap/slapd.d
              default slapd configuration directory

SEE ALSO
       ldap(3),  slapd-bdb(5),  slapd-config(5),  slapd-dnssrv(5),  slapd-hdb(5),  slapd-ldap(5),
       slapd-ldif(5), slapd-mdb(5), slapd-meta(5), slapd-monitor(5), slapd-ndb(5), slapd-null(5),
       slapd-passwd(5),    slapd-perl(5),    slapd-relay(5),    slapd-shell(5),     slapd-sql(5),
       slapd.conf(5),    slapd.overlays(5),    slapd(8).     "OpenLDAP   Administrator's   Guide"
       (http://www.OpenLDAP.org/doc/admin/)

ACKNOWLEDGEMENTS
       OpenLDAP Software is developed and maintained by The OpenLDAP  Project  <http://www.openl‐
       dap.org/>.  OpenLDAP Software is derived from University of Michigan LDAP 3.3 Release.



OpenLDAP                                    2014/09/20                          SLAPD.BACKENDS(5)