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       bdb    This was the recommended primary backend through OpenLDAP 2.3, but it has since been superseded by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       hdb    This was the recommended primary backend through OpenLDAP 2.4.40 but it has since been  superseded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.