guide/admin/slapdconfig.sdf

# $OpenLDAP$
# Copyright 1999-2021 The OpenLDAP Foundation, All Rights Reserved.
# COPYING RESTRICTIONS APPLY, see COPYRIGHT.

H1: The slapd Configuration File

This chapter describes configuring {{slapd}}(8) via the {{slapd.conf}}(5)
configuration file.  {{slapd.conf}}(5) has been deprecated and should
only be used if your site requires one of the backends that hasn't yet
been updated to work with the newer {{slapd-config}}(5) system.  Configuring
{{slapd}}(8) via {{slapd-config}}(5) is described in the previous chapter.

The {{slapd.conf}}(5) file is normally installed in the
{{EX:/usr/local/etc/openldap}} directory.  An alternate configuration
file location can be specified via a command-line option to {{slapd}}(8).


H2: Configuration File Format

The {{slapd.conf}}(5) file consists of three types of configuration
information: global, backend specific, and database specific.  Global
information is specified first, followed by information associated
with a particular backend type, which is then followed by information
associated with a particular database instance.  Global directives can
be overridden in backend and/or database directives, and backend directives
can be overridden by database directives.

Blank lines and comment lines beginning with a '{{EX:#}}' character
are ignored.  If a line begins with whitespace, it is considered a
continuation of the previous line (even if the previous line is a
comment).

The general format of slapd.conf is as follows:

>	# global configuration directives
>	<global config directives>
>
>	# backend definition
>	backend <typeA>
>	<backend-specific directives>
>
>	# first database definition & config directives
>	database <typeA>
>	<database-specific directives>
>
>	# second database definition & config directives
>	database <typeB>
>	<database-specific directives>
>
>	# second database definition & config directives
>	database <typeA>
>	<database-specific directives>
>
>	# subsequent backend & database definitions & config directives
>	...

A configuration directive may take arguments.  If so, they are
separated by whitespace.  If an argument contains whitespace,
the argument should be enclosed in double quotes {{EX:"like this"}}. If
an argument contains a double quote or a backslash character `{{EX:\}}',
the character should be preceded by a backslash character `{{EX:\}}'.

The distribution contains an example configuration file that will
be installed in the {{F: /usr/local/etc/openldap}} directory.
A number of files containing schema definitions (attribute types
and object classes) are also provided in the
{{F: /usr/local/etc/openldap/schema}} directory.


H2: Configuration File Directives

This section details commonly used configuration directives.  For
a complete list, see the {{slapd.conf}}(5) manual page.  This section
separates the configuration file directives into global,
backend-specific and data-specific categories, describing each
directive and its default value (if any), and giving an example of
its use.


H3: Global Directives

Directives described in this section apply to all backends
and databases unless specifically overridden in a backend or
database definition.  Arguments that should be replaced
by actual text are shown in brackets {{EX:<>}}.


H4: access to <what> [ by <who> [<accesslevel>] [<control>] ]+

This directive grants access (specified by <accesslevel>) to a set
of entries and/or attributes (specified by <what>) by one or more
requestors (specified by <who>).  See the {{SECT:Access Control}} section of
this guide for basic usage.

!if 0
More details discussion of this directive can be found in the
{{SECT:Advanced Access Control}} chapter.
!endif

Note: If no {{EX:access}} directives are specified, the default
access control policy, {{EX:access to * by * read}}, allows all
both authenticated and anonymous users read access.


H4: attributetype <{{REF:RFC4512}} Attribute Type Description>

This directive defines an attribute type.
Please see the {{SECT:Schema Specification}} chapter
for information regarding how to use this directive.

H4: idletimeout <integer>

Specify the number of seconds to wait before forcibly closing
an idle client connection.  An idletimeout of 0, the default,
disables this feature.


H4: include <filename>

This directive specifies that slapd should read additional
configuration information from the given file before continuing
with the next line of the current file. The included file should
follow the normal slapd config file format.  The file is commonly
used to include files containing schema specifications.

Note: You should be careful when using this directive - there is
no small limit on the number of nested include directives, and no
loop detection is done.

H4: loglevel <level>

This directive specifies the level at which log statements
and operation statistics should be sent to syslog (currently logged to
the {{syslogd}}(8) {{EX:LOG_LOCAL4}} facility). You must have
configured OpenLDAP {{EX:--enable-debug}} (the default) for this
to work, except for the two statistics levels, which are always
enabled. Log levels may be specified as integers or by keyword.
Multiple log levels may be used and the levels are additive.
The possible values for <integer> are:

!block table; colaligns="RL"; align=Center; \
	title="Table 6.1: Logging Levels"
Level	Keyword		Description
-1	any		enable all debugging
0			no debugging
1	(0x1 trace)	trace function calls
2	(0x2 packets)	debug packet handling
4	(0x4 args)	heavy trace debugging
8	(0x8 conns)	connection management
16	(0x10 BER)	print out packets sent and received
32	(0x20 filter)	search filter processing
64	(0x40 config)	configuration processing
128	(0x80 ACL)	access control list processing
256	(0x100 stats)	stats log connections/operations/results
512	(0x200 stats2)	stats log entries sent
1024	(0x400 shell)	print communication with shell backends
2048	(0x800 parse)	print entry parsing debugging
16384	(0x4000 sync)	syncrepl consumer processing
32768	(0x8000 none)	only messages that get logged regardless of configured log level
!endblock

The desired log level can be input as a single integer that
combines the (ORed) desired levels, both in decimal or in hexadecimal
notation, as a list of integers (that are ORed internally), or as a list of the names that are shown between brackets, such that

>		loglevel 129
>		loglevel 0x81
>		loglevel 128 1
>		loglevel 0x80 0x1
>		loglevel acl trace

are equivalent.

\Examples:

E: loglevel -1

This will enable all log levels.

E: loglevel conns filter

Just log the connection and search filter processing.

E: loglevel none

Log those messages that are logged regardless of the configured loglevel. This
differs from setting the log level to 0, when no logging occurs. At least the
{{EX:None}} level is required to have high priority messages logged.

\Default:

E: loglevel stats

Basic stats logging is configured by default.

H4: objectclass <{{REF:RFC4512}} Object Class Description>

This directive defines an object class.
Please see the {{SECT:Schema Specification}} chapter for
information regarding how to use this directive.


H4: referral <URI>

This directive specifies the referral to pass back when slapd
cannot find a local database to handle a request.

\Example:

>	referral ldap://root.openldap.org

This will refer non-local queries to the global root LDAP server
at the OpenLDAP Project. Smart LDAP clients can re-ask their
query at that server, but note that most of these clients are
only going to know how to handle simple LDAP URLs that
contain a host part and optionally a distinguished name part.


H4: sizelimit <integer>

This directive specifies the maximum number of entries to return
from a search operation.

\Default:

>	sizelimit 500

See the {{SECT:Limits}} section of this guide and {{slapd.conf}}(5)
for more details.

H4: timelimit <integer>

This directive specifies the maximum number of seconds (in real
time) slapd will spend answering a search request. If a
request is not finished in this time, a result indicating an
exceeded timelimit will be returned.

\Default:

>	timelimit 3600

See the {{SECT:Limits}} section of this guide and {{slapd.conf}}(5)
for more details.


H3: General Backend Directives

Directives in this section apply only to the backend in which
they are defined. They are supported by every type of backend.
Backend directives apply to all databases instances of the
same type and, depending on the directive, may be overridden
by database directives.

H4: backend <type>

This directive marks the beginning of a backend declaration.
{{EX:<type>}} should be one of the
supported backend types listed in Table 6.2.

!block table; align=Center; coltags="EX,N"; \
	title="Table 6.2: Database Backends"
Types	Description
asyncmeta	Asynchronous Metadirectory backend
config	Slapd configuration backend
dnssrv	DNS SRV backend
ldap	Lightweight Directory Access Protocol (Proxy) backend
ldif	Lightweight Data Interchange Format backend
mdb	Memory-Mapped DB backend
meta	Metadirectory backend
monitor	Monitor backend
ndb	MySQL NDB backend
null	Null backend
passwd	Provides read-only access to {{passwd}}(5)
perl	Perl Programmable backend
relay	Relay backend
sock	Socket backend
sql	SQL Programmable backend
wt	WiredTiger backend
!endblock

\Example:

>	backend mdb
>	idlexp 16

This marks the beginning of a new {{TERM:MDB}} backend
definition. At present, only back-mdb implements any options
of this type, so this setting is not needed for any other backends.


H3: General Database Directives

Directives in this section apply only to the database in which
they are defined. They are supported by every type of database.

H4: database <type>

This directive marks the beginning of a database instance
declaration.
{{EX:<type>}} should be one of the
supported backend types listed in Table 6.2.

\Example:

>	database mdb

This marks the beginning of a new {{TERM:MDB}} database instance
declaration.


H4: limits <selector> <limit> [<limit> [...]]

Specify time and size limits based on the operation's initiator or base
DN.

See the {{SECT:Limits}} section of this guide and {{slapd.conf}}(5)
for more details.


H4: readonly { on | off }

This directive puts the database into "read-only" mode. Any
attempts to modify the database will return an "unwilling to
perform" error.  If set on a consumer, modifications sent by
syncrepl will still occur.

\Default:

>	readonly off


H4: rootdn <DN>

This directive specifies the DN that is not subject to
access control or administrative limit restrictions for
operations on this database.  The DN need not refer to
an entry in this database or even in the directory. The
DN may refer to a SASL identity.

Entry-based Example:

>	rootdn "cn=Manager,dc=example,dc=com"

SASL-based Example:

>	rootdn "uid=root,cn=example.com,cn=digest-md5,cn=auth"

See the {{SECT:SASL Authentication}} section for information on
SASL authentication identities.


H4: rootpw <password>

This directive can be used to specifies a password for the DN for
the rootdn (when the rootdn is set to a DN within the database).

\Example:

>	rootpw secret

It is also permissible to provide hash of the password in {{REF:RFC2307}}
form.  {{slappasswd}}(8) may be used to generate the password hash.

\Example:

>	rootpw {SSHA}ZKKuqbEKJfKSXhUbHG3fG8MDn9j1v4QN

The hash was generated using the command {{EX:slappasswd -s secret}}.


H4: suffix <dn suffix>

This directive specifies the DN suffix of queries that will be
passed to this backend database. Multiple suffix lines can be
given, and at least one is required for each database
definition.

\Example:

>	suffix "dc=example,dc=com"

Queries with a DN ending in "dc=example,dc=com"
will be passed to this backend.

Note: When the backend to pass a query to is selected, slapd
looks at the suffix line(s) in each database definition in the
order they appear in the file. Thus, if one database suffix is a
prefix of another, it must appear after it in the config file.


H4: syncrepl

>	syncrepl rid=<replica ID>
>		provider=ldap[s]://<hostname>[:port]
>		searchbase=<base DN>
>		[type=refreshOnly|refreshAndPersist]
>		[interval=dd:hh:mm:ss]
>		[retry=[<retry interval> <# of retries>]+]
>		[filter=<filter str>]
>		[scope=sub|one|base]
>		[attrs=<attr list>]
>		[exattrs=<attr list>]
>		[attrsonly]
>		[sizelimit=<limit>]
>		[timelimit=<limit>]
>		[schemachecking=on|off]
>		[network-timeout=<seconds>]
>		[timeout=<seconds>]
>		[bindmethod=simple|sasl]
>		[binddn=<DN>]
>		[saslmech=<mech>]
>		[authcid=<identity>]
>		[authzid=<identity>]
>		[credentials=<passwd>]
>		[realm=<realm>]
>		[secprops=<properties>]
>		[keepalive=<idle>:<probes>:<interval>]
>		[starttls=yes|critical]
>		[tls_cert=<file>]
>		[tls_key=<file>]
>		[tls_cacert=<file>]
>		[tls_cacertdir=<path>]
>		[tls_reqcert=never|allow|try|demand]
>		[tls_cipher_suite=<ciphers>]
>		[tls_crlcheck=none|peer|all]
>		[tls_protocol_min=<major>[.<minor>]]
>		[suffixmassage=<real DN>]
>		[logbase=<base DN>]
>		[logfilter=<filter str>]
>		[syncdata=default|accesslog|changelog]


This directive specifies the current database as a consumer of the
provider content by establishing the current {{slapd}}(8) as a
replication consumer site running a syncrepl replication engine.
The provider database is located at the replication provider site
specified by the {{EX:provider}} parameter. The consumer database is
kept up-to-date with the provider content using the LDAP Content
Synchronization protocol. See {{REF:RFC4533}}
for more information on the protocol.

The {{EX:rid}} parameter is used for identification of the current
{{EX:syncrepl}} directive within the replication consumer server,
where {{EX:<replica ID>}} uniquely identifies the syncrepl specification
described by the current {{EX:syncrepl}} directive. {{EX:<replica ID>}}
is non-negative and is no more than three decimal digits in length.

The {{EX:provider}} parameter specifies the replication provider site
containing the provider content as an LDAP URI. The {{EX:provider}}
parameter specifies a scheme, a host and optionally a port where the
provider slapd instance can be found. Either a domain name or IP
address may be used for <hostname>. Examples are
{{EX:ldap://provider.example.com:389}} or {{EX:ldaps://192.168.1.1:636}}.
If <port> is not given, the standard LDAP port number (389 or 636) is used.
Note that the syncrepl uses a consumer-initiated protocol, and hence its
specification is located on the consumer.

The content of the syncrepl consumer is defined using a search
specification as its result set. The consumer slapd will
send search requests to the provider slapd according to the search
specification. The search specification includes {{EX:searchbase}},
{{EX:scope}}, {{EX:filter}}, {{EX:attrs}}, {{EX:exattrs}}, {{EX:attrsonly}},
{{EX:sizelimit}}, and {{EX:timelimit}} parameters as in the normal
search specification. The {{EX:searchbase}} parameter has no
default value and must always be specified. The {{EX:scope}} defaults
to {{EX:sub}}, the {{EX:filter}} defaults to {{EX:(objectclass=*)}},
{{EX:attrs}} defaults to {{EX:"*,+"}} to replicate all user and operational
attributes, and {{EX:attrsonly}} is unset by default. Both {{EX:sizelimit}}
and {{EX:timelimit}} default to "unlimited", and only positive integers
or "unlimited" may be specified. The {{EX:exattrs}} option may also be used
to specify attributes that should be omitted from incoming entries.

The {{TERM[expand]LDAP Sync}} protocol has two operation
types: {{EX:refreshOnly}} and {{EX:refreshAndPersist}}.
The operation type is specified by the {{EX:type}} parameter.
In the {{EX:refreshOnly}} operation, the next synchronization search operation
is periodically rescheduled at an interval time after each
synchronization operation finishes. The interval is specified
by the {{EX:interval}} parameter. It is set to one day by default.
In the {{EX:refreshAndPersist}} operation, a synchronization search
remains persistent in the provider {{slapd}} instance. Further updates to the
provider will generate {{EX:searchResultEntry}} to the consumer slapd
as the search responses to the persistent synchronization search.

If an error occurs during replication, the consumer will attempt to reconnect
according to the retry parameter which is a list of the <retry interval>
and <# of retries> pairs. For example, retry="60 10 300 3" lets the consumer
retry every 60 seconds for the first 10 times and then retry every 300 seconds
for the next three times before stop retrying. + in <#  of retries> means
indefinite number of retries until success.

The schema checking can be enforced at the LDAP Sync consumer site
by turning on the {{EX:schemachecking}} parameter.
If it is turned on, every replicated entry will be checked for its
schema as the entry is stored on the consumer.
Every entry in the consumer should contain those attributes
required by the schema definition.
If it is turned off, entries will be stored without checking
schema conformance. The default is off.

The {{EX:network-timeout}} parameter sets how long the consumer will
wait to establish a network connection to the provider.  Once a
connection is established, the {{EX:timeout}} parameter determines how
long the consumer will wait for the initial Bind request to complete.  The
defaults for these parameters come from {{ldap.conf}}(5).

The {{EX:binddn}} parameter gives the DN to bind as for the
syncrepl searches to the provider slapd. It should be a DN
which has read access to the replication content in the
provider database.

The {{EX:bindmethod}} is {{EX:simple}} or {{EX:sasl}},
depending on whether simple password-based authentication or
{{TERM:SASL}} authentication is to be used when connecting
to the provider {{slapd}} instance.

Simple authentication should not be used unless adequate data
integrity and confidentiality protections are in place (e.g. TLS
or IPsec). Simple authentication requires specification of {{EX:binddn}}
and {{EX:credentials}} parameters.

SASL authentication is generally recommended.  SASL authentication
requires specification of a mechanism using the {{EX:saslmech}} parameter.
Depending on the mechanism, an authentication identity and/or
credentials can be specified using {{EX:authcid}} and {{EX:credentials}},
respectively.  The {{EX:authzid}} parameter may be used to specify
an authorization identity.

The {{EX:realm}} parameter specifies a realm which a certain
mechanisms authenticate the identity within. The {{EX:secprops}}
parameter specifies Cyrus SASL security properties.

The {{EX:keepalive}} parameter sets the values of idle, probes, and interval
used to check whether a socket is alive;  idle is the number of seconds a
connection needs to remain idle before TCP starts sending keepalive probes;
probes is the maximum number of keepalive probes TCP should send before
dropping the connection; interval is interval in seconds between individual
keepalive probes.  Only some systems support the customization of these
values; the keepalive parameter is ignored otherwise, and system-wide
settings are used. For example, keepalive="240:10:30" will send a keepalive
probe 10 times, every 30 seconds, after 240 seconds of idle activity.  If
no response to the probes is received, the connection will be dropped.

The {{EX:starttls}} parameter specifies use of the StartTLS extended
operation to establish a TLS session before authenticating to the provider.
If the {{EX:critical}} argument is supplied, the session will be aborted
if the StartTLS request fails.  Otherwise the syncrepl session continues
without TLS.  The tls_reqcert setting defaults to {{EX:"demand"}} and the
other TLS settings default to the same as the main slapd TLS settings.

The {{EX:suffixmassage}} parameter allows the consumer to pull entries
from a remote directory whose DN suffix differs from the local directory.
The portion of the remote entries' DNs that matches the searchbase will
be replaced with the suffixmassage DN.

Rather than replicating whole entries, the consumer can query logs
of data modifications.  This mode of operation is referred to as
{{delta syncrepl}}.  In addition to the above parameters, the
{{EX:logbase}} and {{EX:logfilter}} parameters must be set appropriately
for the log that will be used. The {{EX:syncdata}} parameter must
be set to either {{EX:"accesslog"}} if the log conforms to the
{{slapo-accesslog}}(5) log format, or {{EX:"changelog"}} if the log
conforms to the obsolete {{changelog}} format. If the {{EX:syncdata}}
parameter is omitted or set to {{EX:"default"}} then the log
parameters are ignored.

The {{syncrepl}} replication mechanism is supported by the {{mdb}} backend.

See the {{SECT:LDAP Sync Replication}} chapter of this guide for
more information on how to use this directive.


H4: updateref <URL>

This directive is only applicable in a {{replica}} (or {{shadow}})
{{slapd}}(8) instance. It
specifies the URL to return to clients which submit update
requests upon the replica.
If specified multiple times, each {{TERM:URL}} is provided.

\Example:

>	updateref	ldap://provider.example.net


H3: MDB Backend Directives

Directives in this category only apply to the {{TERM:MDB}}
database backend. They will apply to all "database mdb"
instances in the configuration. For a complete reference
of MDB backend configuration directives, see {{slapd-mdb}}(5).

H4: idlexp <exponent>

Specify a power of 2 for the maximum size of an index slot.
The default is 16, yielding a maximum slot size of 2^16 or 65536.
The specified value must be in the range of 16-31.

This setting helps with the case where certain search filters are
slow to return results due to an index slot having collapsed to a
range value.  This occurs when the number of candidate entries that
match the filter for the index slot exceed the configured slot size.

If this setting is decreased on a server with existing {{TERM:MDB}}
databases, each db will immediately need its indices to be rebuilt
while slapd is offline with the "slapindex -q -t" command.

If this setting is increased on a server with existing {{TERM:MDB}}
databases, each db will need its indices rebuilt to take advantage
of the change for indices that have already been converted to ranges.


H3: MDB Database Directives

Directives in this category only apply to the {{TERM:MDB}}
database backend.
That is, they must follow a "database mdb" line
and come before any subsequent "backend" or "database" lines.
For a complete reference of MDB configuration directives, see {{slapd-mdb}}(5).

H4: directory <directory>

This directive specifies the directory where the MDB files
containing the database and associated indices live.

\Default:

>	directory /usr/local/var/openldap-data

H4: checkpoint <kbyte> <min>

This directive specifies the frequency for flushing the database disk
buffers. This directive is only needed if the {{dbnosync}} option is
{{EX:TRUE}}.
The checkpoint 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. Note: currently the _kbyte_ setting is unimplemented.

\Example:

>   checkpoint: 1024 10

H4: dbnosync: { TRUE | FALSE }

This directive causes on-disk database contents to not be immediately
synchronized with in memory changes upon change.  Setting this option
to {{EX:TRUE}} may improve performance at the expense of data integrity.


H4: envflags: {nosync,nometasync,writemap,mapasync,nordahead}

This option specifies flags for finer-grained control of  the  LMDB  library's
operation.

* {{F:nosync}}: This is exactly the same as the dbnosync directive.

* {{F:nometasync}}: Flush the data on a commit, but skip the sync of the meta
page. This mode is slightly faster than doing a full sync, but can
potentially lose the last committed transaction if the operating system
crashes. If both nometasync and nosync are set, the nosync flag takes
precedence.

* {{F:writemap}}: Use a writable memory map instead of just read-only. This
speeds up write operations but makes the database vulnerable to corruption in
case any bugs in slapd cause stray writes into the mmap region.

* {{F:mapasync}}: When using a writable memory map and performing flushes on
each commit, use an asynchronous flush instead of a synchronous flush (the
default). This option has no effect if writemap has not been set. It also has
no effect if nosync is set.

* {{F:nordahead}}: Turn off file readahead. Usually the OS performs readahead
on every read request. This usually boosts read performance but can be
harmful to random access read performance if the system's memory is full and
the DB is larger than RAM. This option is not implemented on Windows.


H4: index: {<attrlist> | default} [pres,eq,approx,sub,none]

This directive specifies the indices to maintain for the given
attribute. If only an {{EX:<attrlist>}} is given, the default
indices are maintained. The index keywords correspond to the
common types of matches that may be used in an LDAP search filter.

\Example:

>   index: default pres,eq
>   index: uid
>   index: cn,sn pres,eq,sub
>   index: objectClass eq

The first line sets the default set of indices to maintain to
present and equality.  The second line causes the default (pres,eq)
set of indices to be maintained for the {{EX:uid}} attribute type.
The third line causes present, equality, and substring indices to
be maintained for {{EX:cn}} and {{EX:sn}} attribute types.  The
fourth line causes an equality index for the {{EX:objectClass}}
attribute type.

There is no index keyword for inequality matches. Generally these
matches do not use an index. However, some attributes do support
indexing for inequality matches, based on the equality index.

A substring index can be more explicitly specified as {{EX:subinitial}},
{{EX:subany}}, or {{EX:subfinal}}, corresponding to the three
possible components
of a substring match filter. A subinitial index only indexes
substrings that appear at the beginning of an attribute value.
A subfinal index only indexes substrings that appear at the end
of an attribute value, while subany indexes substrings that occur
anywhere in a value.

Note that by default, setting an index for an attribute also
affects every subtype of that attribute. E.g., setting an equality
index on the {{EX:name}} attribute causes {{EX:cn}}, {{EX:sn}}, and every other
attribute that inherits from {{EX:name}} to be indexed.

By default, no indices are maintained.  It is generally advised
that minimally an equality index upon objectClass be maintained.

>   index: objectClass eq

Additional indices should be configured corresponding to the
most common searches that are used on the database.
Presence indexing should not be configured for an attribute
unless the attribute occurs very rarely in the database, and
presence searches on the attribute occur very frequently during
normal use of the directory. Most applications don't use presence
searches, so usually presence indexing is not very useful.


H4: maxentrysize: <bytes>

Specify the maximum size of an entry in bytes. Attempts to store
an entry larger than this size will be rejected with the error
LDAP_ADMINLIMIT_EXCEEDED. The default is 0, which is unlimited.


H4: maxreaders: <integer>

This directive specifies the maximum number of threads that may have
concurrent read access to the database. Tools such as slapcat count as a
single thread, in addition to threads in any active slapd processes. The
default is 126.


H4: maxsize: <bytes>

This directive specifies the maximum size of the database in bytes. A memory
map of this size is allocated at startup time and the database will not be
allowed to grow beyond this size. The default is 10485760 bytes (10MB). This
setting may be changed upward if the configured limit needs to be increased.

Note: It is important to set this to as large a value as possible, (relative
to anticipated growth of the actual data over time) since growing the size
later may not be practical when the system is under heavy load.


H4: mode: { <octal> | <symbolic> }

This directive specifies the file protection mode that newly
created database index files should have. This can be in the form
{{EX:0600}} or {{EX:-rw-------}}

\Default:

>   mode: 0600


H4: multival: { <attrlist> | default } <integer> hi,<integer> lo

Specify the number of values for which a multivalued attribute is
stored in a separate table. Normally entries are stored as a single
blob inside the database. When an entry gets very large or contains
attributes with a very large number of values, modifications on that
entry may get very slow. Splitting the large attributes out to a separate
table can improve the performance of modification operations.
The threshold is specified as a pair of integers. If the number of
values exceeds the hi threshold the values will be split out. If
a modification deletes enough values to bring an attribute below
the lo threshold the values will be removed from the separate
table and merged back into the main entry blob.
The threshold can be set for a specific list of attributes, or
the default can be configured for all other attributes.
The default value for both hi and lo thresholds is UINT_MAX, which keeps
all attributes in the main blob.

In addition to increasing write performance of operations the use of
multival can also decrease fragmentation of the primary {{TERM:MDB}} database.


H4: rtxnsize: <entries>

This directive specifies the maximum number of entries to process in a single
read transaction when executing a large search. Long-lived read transactions
prevent old database pages from being reused in write transactions, and so
can cause significant growth of the database file when there is heavy write
traffic. This setting causes the read transaction in large searches to be
released and reacquired after the given number of entries has been read, to
give writers the opportunity to reclaim old database pages. The default is
10000.


H4: searchstack: <integer>

Specify the depth of the stack used for search filter evaluation.
Search filters are evaluated on a stack to accommodate nested {{EX:AND}} /
{{EX:OR}} clauses. An individual stack is allocated for 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 separate allocations
can have a major negative impact on server performance, but specifying
too much stack will also consume a great deal of memory. Each search
uses 512K bytes per level on a 32-bit machine, or 1024K bytes per level
on a 64-bit machine. The default stack depth is 16, thus 8MB or 16MB
per thread is used on 32 and 64 bit machines, respectively. Also the
512KB size of a single stack slot is set by a compile-time constant which
may be changed if needed; the code must be recompiled for the change
to take effect.

\Default:

>   searchstack: 16


H4: Sample Entry

>database mdb
>suffix: "dc=example,dc=com"
>directory: /usr/local/var/openldap-data
>index: objectClass eq


H2: Configuration File Example

The following is an example configuration file, interspersed
with explanatory text. It defines two databases to handle
different parts of the {{TERM:X.500}} tree; both are {{TERM:MDB}}
database instances. The line numbers shown are provided for
reference only and are not included in the actual file. First, the
global configuration section:

E:  1.    # example config file - global configuration section
E:  2.    include /usr/local/etc/schema/core.schema
E:  3.    referral ldap://root.openldap.org
E:  4.    access to * by * read

Line 1 is a comment. Line 2 includes another config file
which contains {{core}} schema definitions.
The {{EX:referral}} directive on line 3
means that queries not local to one of the databases defined
below will be referred to the LDAP server running on the
standard port (389) at the host {{EX:root.openldap.org}}.

Line 4 is a global access control.  It applies to all
entries (after any applicable database-specific access
controls).

The next section of the configuration file defines a MDB
backend that will handle queries for things in the
"dc=example,dc=com" portion of the tree. The
database is to be replicated to two replica slapds, one on
truelies, the other on judgmentday. Indices are to be
maintained for several attributes, and the {{EX:userPassword}}
attribute is to be protected from unauthorized access.

E:  5.    # MDB definition for the example.com
E:  6.    database mdb
E:  7.    suffix "dc=example,dc=com"
E:  8.    directory /usr/local/var/openldap-data
E:  9.    rootdn "cn=Manager,dc=example,dc=com"
E: 10.    rootpw secret
E: 11.    # indexed attribute definitions
E: 12.    index uid pres,eq
E: 13.    index cn,sn pres,eq,approx,sub
E: 14.    index objectClass eq
E: 15.    # database access control definitions
E: 16.    access to attrs=userPassword
E: 17.        by self write
E: 18.        by anonymous auth
E: 19.        by dn.base="cn=Admin,dc=example,dc=com" write
E: 20.        by * none
E: 21.    access to *
E: 22.        by self write
E: 23.        by dn.base="cn=Admin,dc=example,dc=com" write
E: 24.        by * read

Line 5 is a comment. The start of the database definition is marked
by the database keyword on line 6. Line 7 specifies the DN suffix
for queries to pass to this database. Line 8 specifies the directory
in which the database files will live.

Lines 9 and 10 identify the database {{super-user}} entry and associated
password. This entry is not subject to access control or size or
time limit restrictions.

Lines 12 through 14 indicate the indices to maintain for various
attributes.

Lines 16 through 24 specify access control for entries in this
database. For all applicable entries, the {{EX:userPassword}} attribute is writable
by the entry itself and by the "admin" entry.  It may be used for
authentication/authorization purposes, but is otherwise not readable.
All other attributes are writable by the entry and the "admin"
entry, but may be read by all users (authenticated or not).

The next section of the example configuration file defines another
MDB database. This one handles queries involving the
{{EX:dc=example,dc=net}} subtree but is managed by the same entity
as the first database.  Note that without line 39, the read access
would be allowed due to the global access rule at line 4.

E: 33.    # MDB definition for example.net
E: 34.    database mdb
E: 35.    suffix "dc=example,dc=net"
E: 36.    directory /usr/local/var/openldap-data-net
E: 37.    rootdn "cn=Manager,dc=example,dc=com"
E: 38.    index objectClass eq
E: 39.    access to * by users read