2 # Copyright 2007-2008 The OpenLDAP Foundation, All Rights Reserved.
3 # COPYING RESTRICTIONS APPLY, see COPYRIGHT.
8 H2: Berkeley DB Backends
13 The {{bdb}} backend to {{slapd}}(8) is the recommended primary backend for a
14 normal {{slapd}} database. It uses the Oracle Berkeley DB ({{TERM:BDB}})
15 package to store data. It makes extensive use of indexing and caching
16 (see the {{SECT:Tuning}} section) to speed data access.
18 {{hdb}} is a variant of the {{bdb}} backend that uses a hierarchical database
19 layout which supports subtree renames. It is otherwise identical to the {{bdb}}
20 behavior, and all the same configuration options apply.
22 Note: An {{hdb}} database needs a large {{idlcachesize}} for good search performance,
23 typically three times the {{cachesize}} (entry cache size) or larger.
25 H3: back-bdb/back-hdb Configuration
29 H3: Further Information
38 The LDAP backend to {{slapd}}(8) is not an actual database; instead it acts
39 as a proxy to forward incoming requests to another LDAP server. While
40 processing requests it will also chase referrals, so that referrals are fully
41 processed instead of being returned to the {{slapd}} client.
43 Sessions that explicitly {{Bind}} to the {{back-ldap}} database always create
44 their own private connection to the remote LDAP server. Anonymous sessions
45 will share a single anonymous connection to the remote server. For sessions
46 bound through other mechanisms, all sessions with the same DN will share the
47 same connection. This connection pooling strategy can enhance the proxy's
48 efficiency by reducing the overhead of repeatedly making/breaking multiple
51 The ldap database can also act as an information service, i.e. the identity
52 of locally authenticated clients is asserted to the remote server, possibly
53 in some modified form. For this purpose, the proxy binds to the remote server
54 with some administrative identity, and, if required, authorizes the asserted
57 It is heavily used by a lot of other {{SECT: Backends}} and {{SECT: Overlays}}.
59 H3: back-ldap Configuration
61 As previously mentioned, {{slapd-ldap(5)}} is used behind the scenes by many
62 other {{SECT: Backends}} and {{SECT: Overlays}}. Some of them merely provide a
63 few configuration directive themselves, but have available to the administrator
64 the whole of the {{slapd-ldap(5)}} options.
66 For example, the {{SECT: Translucent Proxy}}, which retrieves entries from a
67 remote LDAP server that can be partially overridden by the defined database, has
68 only four specific {{translucent-}} directives, but can be configured using any
69 of the normal {{slapd-ldap(5)}} options. See {[slapo-translucent(5)}} for details.
71 Other {{SECT: Overlays}} allow you to tag directives in front of a normal
72 {{slapd-ldap(5)}} directive. For example, the {{slapo-chain(5)}} overlay does
75 {{"There are very few chain overlay specific directives; however, directives
76 related to the instances of the ldap backend that may be implicitly instantiated
77 by the overlay may assume a special meaning when used in conjunction with this
78 overlay. They are described in slapd-ldap(5), and they also need to be prefixed
81 You may have also seen the {{slapd-ldap(5)}} backend used and described in the
82 {{SECT: Push Based}} {{SECT: Replication}} section of the guide.
84 It should therefore be obvious that the {{slapd-ldap(5)}} backend is extremely
85 flexible and heavily used throughout the OpenLDAP Suite.
87 The following is a very simple example, but already the power of the {{slapd-ldap(5)}}
88 backend is seen by use of a {{uri list}}:
91 > suffix "dc=suretecsystems,dc=com"
92 > rootdn "cn=slapd-ldap"
93 > uri ldap://localhost/ ldap://remotehost ldap://remotehost2
95 The URI list is space or comma-separated. Whenever the server that responds
96 is not the first one in the list, the list is rearranged and the responsive
97 server is moved to the head, so that it will be first contacted the next time
98 a connection needs be created.
100 This feature can be used to provide a form of load balancing when using
101 {{SECT: MirrorMode replication}}.
103 As always, refer to the {{slapd-ldap(5)}} man page for the finer details.
106 H3: Further Information
115 The LDIF backend to {{slapd}}(8) is a basic storage backend that stores
116 entries in text files in LDIF format, and exploits the filesystem to create
117 the tree structure of the database. It is intended as a cheap, low performance
120 When using the {{cn=config}} dynamic configuration database with persistent
121 storage, the configuration data is stored using this backend. See {{slapd-config}}(5)
124 H3: back-ldif Configuration
128 H3: Further Information
137 The meta backend to {{slapd}}(8) performs basic LDAP proxying with respect
138 to a set of remote LDAP servers, called "targets". The information contained
139 in these servers can be presented as belonging to a single Directory Information
142 A basic knowledge of the functionality of the {{slapd-ldap}}(5) backend is
143 recommended. This backend has been designed as an enhancement of the ldap
144 backend. The two backends share many features (actually they also share portions
145 of code). While the ldap backend is intended to proxy operations directed
146 to a single server, the meta backend is mainly intended for proxying of
147 multiple servers and possibly naming context masquerading.
149 These features, although useful in many scenarios, may result in excessive
150 overhead for some applications, so its use should be carefully considered.
153 H3: back-meta Configuration
157 H3: Further Information
166 The monitor backend to {{slapd}}(8) is not an actual database; if enabled,
167 it is automatically generated and dynamically maintained by slapd with
168 information about the running status of the daemon.
170 To inspect all monitor information, issue a subtree search with base {{cn=Monitor}},
171 requesting that attributes "+" and "*" are returned. The monitor backend produces
172 mostly operational attributes, and LDAP only returns operational attributes
173 that are explicitly requested. Requesting attribute "+" is an extension which
174 requests all operational attributes.
176 See the {{SECT:Monitoring}} section.
178 H3: back-monitor Configuration
182 H3: Further Information
191 The Null backend to {{slapd}}(8) is surely the most useful part of slapd:
193 * Searches return success but no entries.
194 * Compares return compareFalse.
195 * Updates return success (unless readonly is on) but do nothing.
196 * Binds other than as the rootdn fail unless the database option "bind on" is given.
197 * The slapadd(8) and slapcat(8) tools are equally exciting.
199 Inspired by the {{F:/dev/null}} device.
201 H3: back-null Configuration
205 H3: Further Information
214 The PASSWD backend to {{slapd}}(8) serves up the user account information
215 listed in the system {{passwd}}(5) file.
217 This backend is provided for demonstration purposes only. The DN of each entry
218 is "uid=<username>,<suffix>".
220 H3: back-passwd Configuration
224 H3: Further Information
232 The Perl backend to {{slapd}}(8) works by embedding a {{perl}}(1) interpreter
233 into {{slapd}}(8). Any perl database section of the configuration file
234 {{slapd.conf}}(5) must then specify what Perl module to use. Slapd then creates
235 a new Perl object that handles all the requests for that particular instance of the backend.
237 The Shell backend to {{slapd}}(8) executes external programs to implement
238 operations, and is designed to make it easy to tie an existing database to the
239 slapd front-end. This backend is is primarily intended to be used in prototypes.
241 H3: back-perl/back-shell Configuration
245 H3: Further Information
247 {{slapd-shell}}(5) and {{slapd-perl}}(5)
254 The primary purpose of this {{slapd}}(8) backend is to map a naming context
255 defined in a database running in the same {{slapd}}(8) instance into a
256 virtual naming context, with attributeType and objectClass manipulation, if
257 required. It requires the rwm overlay.
259 This backend and the above mentioned overlay are experimental.
261 H3: back-relay Configuration
265 H3: Further Information
274 The primary purpose of this {{slapd}}(8) backend is to PRESENT information
275 stored in some RDBMS as an LDAP subtree without any programming (some SQL and
276 maybe stored procedures can’t be considered programming, anyway ;).
278 That is, for example, when you (some ISP) have account information you use in
279 an RDBMS, and want to use modern solutions that expect such information in LDAP
280 (to authenticate users, make email lookups etc.). Or you want to synchronize or
281 distribute information between different sites/applications that use RDBMSes
282 and/or LDAP. Or whatever else...
284 It is {{B:NOT}} designed as a general-purpose backend that uses RDBMS instead of
285 BerkeleyDB (as the standard BDB backend does), though it can be used as such with
286 several limitations. Please see {{SECT: LDAP vs RDBMS}} for discussion.
288 The idea is to use some meta-information to translate LDAP queries to SQL queries,
289 leaving relational schema untouched, so that old applications can continue using
290 it without any modifications. This allows SQL and LDAP applications to interoperate
291 without replication, and exchange data as needed.
293 The SQL backend is designed to be tunable to virtually any relational schema without
294 having to change source (through that meta-information mentioned). Also, it uses
295 ODBC to connect to RDBMSes, and is highly configurable for SQL dialects RDBMSes
296 may use, so it may be used for integration and distribution of data on different
297 RDBMSes, OSes, hosts etc., in other words, in highly heterogeneous environment.
299 This backend is experimental.
301 H3: back-sql Configuration
305 H3: Further Information