SLAPD-BDB(5) SLAPD-BDB(5)
NAME
slapd-bdb, slapd-hdb - Berkeley DB backends to slapd
SYNOPSIS
/etc/openldap/slapd.conf
DESCRIPTION
The bdb backend to slapd(8) is the recommended primary backend for a normal slapd database. It uses
the Sleepycat Berkeley DB (BDB) package to store data. It makes extensive use of indexing and
caching to speed data access.
hdb is a variant of the bdb backend that uses a hierarchical database layout which supports subtree
renames. It is otherwise identical to the bdb behavior, and all the same configuration options apply.
It is noted that these options are intended to complement Berkeley DB configuration options set in
the environment's DB_CONFIG file. See Berkeley DB documentation for details on DB_CONFIG configura-tion configuration
tion options. Where there is overlap, settings in DB_CONFIG take precedence.
CONFIGURATION
These slapd.conf options apply to the bdb and hdb backend database. That is, they must follow a
"database bdb" or "database hdb" line and come before any subsequent "backend" or "database" lines.
Other database options are described in the slapd.conf(5) manual page.
cachesize <integer>
Specify the size in entries of the in-memory entry cache maintained by the bdb or hdb backend
database instance. The default is 1000 entries.
cachefree <integer>
Specify the number of entries to free from the entry cache when the cache reaches the cache-size cachesize
size limit. The default is 1 entry.
checkpoint <kbyte> <min>
Specify the frequency for checkpointing the database transaction log. A checkpoint operation
flushes the database buffers to disk and writes a checkpoint record in the log. The check-point checkpoint
point will occur if either <kbyte> data has been written or <min> minutes have passed since
the last checkpoint. Both arguments default to zero, in which case they are ignored. When the
<min> argument is non-zero, an internal task will run every <min> minutes to perform the
checkpoint. See the Berkeley DB reference guide for more details.
dbconfig <Berkeley-DB-setting>
Specify a configuration directive to be placed in the DB_CONFIG file of the database direc-tory. directory.
tory. The dbconfig directive is just a convenience to allow all necessary configuration to be
set in the slapd.conf file. The options set using this directive will only be written to the
DB_CONFIG file if no such file existed at server startup time. This allows one to set initial
values without overwriting/destroying a DB_CONFIG file that was already customized through
other means. This directive may be specified multiple times, as needed. For example:
dbconfig set_cachesize 0 1048576 0
dbconfig set_lg_bsize 2097152
dbnosync
Specify that on-disk database contents should not be immediately synchronized with in memory
changes. Enabling this option may improve performance at the expense of data security. See
the Berkeley DB reference guide for more details.
directory <directory>
Specify the directory where the BDB files containing this database and associated indexes
live. A separate directory must be specified for each database. The default is
/var/db/openldap/openldap-data.
dirtyread
Allow reads of modified but not yet committed data. Usually transactions are isolated to pre-vent prevent
vent other operations from accessing uncommitted data. This option may improve performance,
but may also return inconsistent results if the data comes from a transaction that is later
aborted. In this case, the modified data is discarded and a subsequent search will return a
different result.
idlcachesize <integer>
Specify the size of the in-memory index cache, in index slots. The default is zero. A larger
value will speed up frequent searches of indexed entries. An hdb database needs a large idl-cachesize idlcachesize
cachesize for good search performance, typically three times the cachesize (entry cache size)
or larger.
index {<attrlist>|default} [pres,eq,approx,sub,<special>]
Specify the indexes to maintain for the given attribute (or list of attributes). Some
attributes only support a subset of indexes. If only an <attr> is given, the indices speci-fied specified
fied for default are maintained. Note that setting a default does not imply that all
attributes will be indexed. Also, for best performance, an eq index should always be config-ured configured
ured for the objectClass attribute.
A number of special index parameters may be specified. The index type sub can be decomposed
into subinitial, subany, and subfinal indices. The special type nolang may be specified to
disallow use of this index by language subtypes. The special type nosubtypes may be specified
to disallow use of this index by named subtypes. Note: changing index settings in
slapd.conf(5) requires rebuilding indices, see slapindex(8); changing index settings dynami-cally dynamically
cally by LDAPModifying "cn=config" automatically causes rebuilding of the indices online in a
background task.
linearindex
Tell slapindex to index one attribute at a time. By default, all indexed attributes in an
entry are processed at the same time. With this option, each indexed attribute is processed
individually, using multiple passes through the entire database. This option improves slapin-dex slapindex
dex performance when the database size exceeds the dbcache size. When the dbcache is large
enough, this option is not needed and will decrease performance. Also by default, slapadd
performs full indexing and so a separate slapindex run is not needed. With this option, sla-padd slapadd
padd does no indexing and slapindex must be used.
lockdetect {oldest|youngest|fewest|random|default}
Specify which transaction to abort when a deadlock is detected. The default is random.
mode <integer>
Specify the file protection mode that newly created database index files should have. The
default is 0600.
searchstack <depth>
Specify the depth of the stack used for search filter evaluation. Search filters are evalu-ated evaluated
ated on a stack to accommodate nested AND / OR clauses. An individual stack is assigned to
each server thread. The depth of the stack determines how complex a filter can be evaluated
without requiring any additional memory allocation. Filters that are nested deeper than the
search stack depth will cause a separate stack to be allocated for that particular search
operation. These allocations can have a major negative impact on server performance, but spec-ifying specifying
ifying too much stack will also consume a great deal of memory. Each search stack uses 512K
bytes per level. The default stack depth is 16, thus 8MB per thread is used.
shm_key <integer>
Specify a key for a shared memory BDB environment. By default the BDB environment uses memory
mapped files. If a non-zero value is specified, it will be used as the key to identify a
shared memory region that will house the environment.
ACCESS CONTROL
The bdb and hdb backends honor access control semantics as indicated in slapd.access(5).
FILES
/etc/openldap/slapd.conf
default slapd configuration file
DB_CONFIG
Berkeley DB configuration file
SEE ALSO
slapd.conf(5), slapd(8), slapadd(8), slapcat(8), slapindex(8), Berkeley DB documentation.
OpenLDAP 2.3.27 2006/08/19 SLAPD-BDB(5)
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