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              been superseded by the mdb backend.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
              explicitly 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 was the recommended primary backend through OpenLDAP 2.4.40 but it  has  since
              been  superseded  by the mdb backend.  It takes care to configure it properly.  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
              subtree renames.

       mdb    This is 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
              backends  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
              further.

       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
              primarily 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.openldap.org/>.  OpenLDAP Software is derived from the University of  Michigan
       LDAP 3.3 Release.