1SLAPD-BDB(5) File Formats Manual SLAPD-BDB(5)
2
6 slapd-bdb, slapd-hdb - Berkeley DB backends to slapd
7
9 /etc/openldap/slapd.conf
10
12 The bdb backend to slapd(8) is the recommended primary backend for a
13 normal slapd database. It uses the Oracle Berkeley DB (BDB) package to
14 store data. It makes extensive use of indexing and caching to speed
15 data access.
16 hdb is a variant of the bdb backend that uses a hierarchical database
18 layout which supports subtree renames. It is otherwise identical to the
19 bdb behavior, and all the same configuration options apply.
20 It is noted that these options are intended to complement Berkeley DB
22 configuration options set in the environment's DB_CONFIG file. See
23 Berkeley DB documentation for details on DB_CONFIG configuration
24 options. Where there is overlap, settings in DB_CONFIG take prece‐
25 dence.
26
28 These slapd.conf options apply to the bdb and hdb backend database.
29 That is, they must follow a "database bdb" or "database hdb" line and
30 come before any subsequent "backend" or "database" lines. Other data‐
31 base options are described in the slapd.conf(5) manual page.
32 cachesize <integer>
34 Specify the size in entries of the in-memory entry cache main‐
35 tained by the bdb or hdb backend database instance. The default
36 is 1000 entries.
37 cachefree <integer>
39 Specify the number of entries to free from the entry cache when
40 the cache reaches the cachesize limit. The default is 1 entry.
41 checkpoint <kbyte> <min>
43 Specify the frequency for checkpointing the database transaction
44 log. A checkpoint operation flushes the database buffers to
45 disk and writes a checkpoint record in the log. The checkpoint
46 will occur if either <kbyte> data has been written or <min> min‐
47 utes have passed since the last checkpoint. Both arguments
48 default to zero, in which case they are ignored. When the <min>
49 argument is non-zero, an internal task will run every <min> min‐
50 utes to perform the checkpoint. See the Berkeley DB reference
51 guide for more details.
52 checksum
54 Enable checksum validation of DB pages whenever they are read
55 from disk. This setting can only be configured before any data‐
56 base files are created.
57 cryptfile <file>
59 Specify the pathname of a file containing an encryption key to
60 use for encrypting the database. Encryption is performed using
61 Berkeley DB's implementation of AES. Note that encryption can
62 only be configured before any database files are created, and
63 changing the key can only be done after destroying the current
64 database and recreating it. Encryption is not enabled by
65 default, and some distributions of Berkeley DB do not support
66 encryption.
67 cryptkey <key>
69 Specify an encryption key to use for encrypting the database.
70 This option may be used when a separate cryptfile is not
71 desired. Only one of cryptkey or cryptfile may be configured.
72 dbconfig <Berkeley-DB-setting>
74 Specify a configuration directive to be placed in the DB_CONFIG
75 file of the database directory. The dbconfig directive is just a
76 convenience to allow all necessary configuration to be set in
77 the slapd.conf file. The options set using this directive will
78 only be written to the DB_CONFIG file if no such file existed at
79 server startup time, otherwise they are completely ignored. This
80 allows one to set initial values without overwriting/destroying
81 a DB_CONFIG file that was already customized through other
82 means. This directive may be specified multiple times, as
83 needed. For example:
84 dbconfig set_cachesize 0 1048576 0
85 dbconfig set_lg_bsize 2097152
86 dbnosync
88 Specify that on-disk database contents should not be immediately
89 synchronized with in memory changes. Enabling this option may
90 improve performance at the expense of data security. See the
91 Berkeley DB reference guide for more details.
92 dbpagesize <dbfile> <size>
94 Specify the page size to use for a particular database file, in
95 units of 1024 bytes. The default for the id2entry file is 16,
96 the default for all other files depends on the size of the
97 underlying filesystem's block size (typically 4 or 8). The max‐
98 imum that BerkeleyDB supports is 64. This setting usually should
99 not need to be changed, but if BerkeleyDB's "db_stat -d" shows a
100 large amount of overflow pages in use in a file, setting a
101 larger size may increase performance at the expense of data
102 integrity. This setting only takes effect when a database is
103 being newly created. See the Berkeley DB reference guide for
104 more details.
105 directory <directory>
107 Specify the directory where the BDB files containing this data‐
108 base and associated indexes live. A separate directory must be
109 specified for each database. The default is /var/openldap-data.
110 dirtyread
112 Allow reads of modified but not yet committed data. Usually
113 transactions are isolated to prevent other operations from
114 accessing uncommitted data. This option may improve perfor‐
115 mance, but may also return inconsistent results if the data
116 comes from a transaction that is later aborted. In this case,
117 the modified data is discarded and a subsequent search will
118 return a different result.
119 dncachesize <integer>
121 Specify the maximum number of DNs in the in-memory DN cache.
122 Ideally this cache should be large enough to contain the DNs of
123 every entry in the database. If set to a smaller value than the
124 cachesize it will be silently increased to equal the cachesize.
125 The default value is 0 which means unlimited, i.e. the DN cache
126 will grow without bound.
127 It should be noted that the DN cache is allowed to temporarily
129 grow beyond the configured size. It does this if many entries
130 are locked when it tries to do a purge, because that means
131 they're legitimately in use. Also, the DN cache never purges
132 entries that have cached children, so depending on the shape of
133 the DIT, it could have lots of cached DNs over the defined
134 limit.
135 idlcachesize <integer>
137 Specify the size of the in-memory index cache, in index slots.
138 The default is zero. A larger value will speed up frequent
139 searches of indexed entries. An hdb database needs a large idl‐
140 cachesize for good search performance, typically three times the
141 cachesize (entry cache size) or larger.
142 index {<attrlist>|default} [pres,eq,approx,sub,<special>]
144 Specify the indexes to maintain for the given attribute (or list
145 of attributes). Some attributes only support a subset of
146 indexes. If only an <attr> is given, the indices specified for
147 default are maintained. Note that setting a default does not
148 imply that all attributes will be indexed. Also, for best per‐
149 formance, an eq index should always be configured for the
150 objectClass attribute.
151 A number of special index parameters may be specified. The
153 index type sub can be decomposed into subinitial, subany, and
154 subfinal indices. The special type nolang may be specified to
155 disallow use of this index by language subtypes. The special
156 type nosubtypes may be specified to disallow use of this index
157 by named subtypes. Note: changing index settings in
158 slapd.conf(5) requires rebuilding indices, see slapindex(8);
159 changing index settings dynamically by LDAPModifying "cn=config"
160 automatically causes rebuilding of the indices online in a back‐
161 ground task.
162 linearindex
164 Tell slapindex to index one attribute at a time. By default, all
165 indexed attributes in an entry are processed at the same time.
166 With this option, each indexed attribute is processed individu‐
167 ally, using multiple passes through the entire database. This
168 option improves slapindex performance when the database size
169 exceeds the dbcache size. When the dbcache is large enough, this
170 option is not needed and will decrease performance. Also by
171 default, slapadd performs full indexing and so a separate
172 slapindex run is not needed. With this option, slapadd does no
173 indexing and slapindex must be used.
174 lockdetect {oldest|youngest|fewest|random|default}
176 Specify which transaction to abort when a deadlock is detected.
177 The default is random.
178 mode <integer>
180 Specify the file protection mode that newly created database
181 index files should have. The default is 0600.
182 searchstack <depth>
184 Specify the depth of the stack used for search filter evalua‐
185 tion. Search filters are evaluated on a stack to accommodate
186 nested AND / OR clauses. An individual stack is assigned to each
187 server thread. The depth of the stack determines how complex a
188 filter can be evaluated without requiring any additional memory
189 allocation. Filters that are nested deeper than the search stack
190 depth will cause a separate stack to be allocated for that par‐
191 ticular search operation. These allocations can have a major
192 negative impact on server performance, but specifying too much
193 stack will also consume a great deal of memory. Each search
194 stack uses 512K bytes per level. The default stack depth is 16,
195 thus 8MB per thread is used.
196 shm_key <integer>
198 Specify a key for a shared memory BDB environment. By default
199 the BDB environment uses memory mapped files. If a non-zero
200 value is specified, it will be used as the key to identify a
201 shared memory region that will house the environment.
202
204 The bdb and hdb backends honor access control semantics as indicated in
205 slapd.access(5).
206
208 /etc/openldap/slapd.conf
209 default slapd configuration file
210 DB_CONFIG
212 Berkeley DB configuration file
213
215 slapd.conf(5), slapd-config(5), slapd(8), slapadd(8), slapcat(8),
216 slapindex(8), Berkeley DB documentation.
217
219 OpenLDAP Software is developed and maintained by The OpenLDAP Project
220 <http://www.openldap.org/>. OpenLDAP Software is derived from Univer‐
221 sity of Michigan LDAP 3.3 Release. Originally begun by Kurt Zeilenga.
222 Caching mechanisms originally designed by Jong-Hyuk Choi. Completion
223 and subsequent work, as well as back-hdb, by Howard Chu.
224OpenLDAP 2.4.23 2010/06/30 SLAPD-BDB(5)