Chapter 4. Plug-in Implemented Server Functionality Reference
This chapter contains reference information on Red Hat Directory Server plug-ins.
The configuration for each part of Directory Server plug-in functionality has its own separate entry and set of attributes under the subtree cn=plugins,cn=config
.
dn: cn=Telephone Syntax,cn=plugins,cn=config objectclass: top objectclass: nsSlapdPlugin objectclass: extensibleObject cn: Telephone Syntax nsslapd-pluginPath: libsyntax-plugin nsslapd-pluginInitfunc: tel_init nsslapd-pluginType: syntax nsslapd-pluginEnabled: on
Some of these attributes are common to all plug-ins while others may be particular to a specific plug-in. Check which attributes are currently being used by a given plug-in by performing an ldapsearch
on the cn=config
subtree.
All plug-ins are instances of the nsSlapdPlugin
object class, which in turn inherits from the extensibleObject
object class. For plug-in configuration attributes to be taken into account by the server, both of these object classes (in addition to the top
object class) must be present in the entry, as shown in the following example:
dn:cn=ACL Plugin,cn=plugins,cn=config objectclass:top objectclass:nsSlapdPlugin objectclass:extensibleObject
4.1. Server Plug-in Functionality Reference
The following tables provide a quick overview of the plug-ins provided with Directory Server, along with their configurable options, configurable arguments, default setting, dependencies, general performance-related information, and further reading. These tables assist in weighing plug-in performance gains and costs and choose the optimal settings for the deployment. The Further Information section cross-references further reading, where this is available.
4.1.1. 7-bit Check Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | NS7bitAtt |
DN of Configuration Entry | cn=7-bit check,cn=plugins,cn=config |
Description | Checks certain attributes are 7-bit clean |
Type | preoperation |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
List of attributes ( | Dependencies |
Database | Performance-Related Information |
None | Further Information |
4.1.2. ACL Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | acl |
DN of Configuration Entry | cn=ACL Plugin,cn=plugins,cn=config |
Description | ACL access check plug-in |
Type | accesscontrol |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
Database | Performance-Related Information |
Access control incurs a minimal performance hit. Leave this plug-in enabled since it is the primary means of access control for the server. | Further Information |
4.1.3. ACL Preoperation Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | acl |
DN of Configuration Entry | cn=ACL preoperation,cn=plugins,cn=config |
Description | ACL access check plug-in |
Type | preoperation |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
Database | Performance-Related Information |
Access control incurs a minimal performance hit. Leave this plug-in enabled since it is the primary means of access control for the server. | Further Information |
4.1.4. Account Policy Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | none |
DN of Configuration Entry | cn=Account Policy Plugin,cn=plugins,cn=config |
Description | Defines a policy to lock user accounts after a certain expiration period or inactivity period. |
Type | object |
Configurable Options | on |
off | Default Setting |
off | Configurable Arguments |
A pointer to a configuration entry which contains the global account policy settings. | Dependencies |
Database | Performance-Related Information |
None | Further Information |
4.1.5. Account Usability Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | acctusability |
DN of Configuration Entry | cn=Account Usability Plugin,cn=plugins,cn=config |
Description | Checks the authentication status, or usability, of an account without actually authenticating as the given user |
Type | preoperation |
Configurable Options | on |
off | Default Setting |
on | Dependencies |
Database | Performance-Related Information |
4.1.6. AD DN Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | addn |
DN of Configuration Entry | cn=addn,cn=plugins,cn=config |
Description |
Enables the usage of Active Directory-formatted user names, such as |
Type | preoperation |
Configurable Options | on |
off | Default Setting |
off | Configurable Arguments |
| Dependencies |
None | Performance-Related Information |
4.1.7. Attribute Uniqueness Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | NSUniqueAttr |
DN of Configuration Entry | cn=Attribute Uniqueness,cn=plugins,cn=config |
Description | Checks that the values of specified attributes are unique each time a modification occurs on an entry. For example, most sites require that a user ID and email address be unique. |
Type | preoperation |
Configurable Options | on |
off | Default Setting |
off | Configurable Arguments |
To check for UID attribute uniqueness in all listed subtrees, enter | Dependencies |
Database | Performance-Related Information |
Directory Server provides the UID Uniqueness Plug-in by default. To ensure unique values for other attributes, create instances of the Attribute Uniqueness Plug-in for those attributes. See the "Using the Attribute Uniqueness Plug-in" section in the Red Hat Directory Server Administration Guide for more information about the Attribute Uniqueness Plug-in. The UID Uniqueness Plug-in is off by default due to operation restrictions that need to be addressed before enabling the plug-in in a multi-supplier replication environment. Turning the plug-in on may slow down Directory Server performance. | Further Information |
4.1.8. Auto Membership Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | Auto Membership |
DN of Configuration Entry | cn=Auto Membership,cn=plugins,cn=config |
Description | Container entry for automember definitions. Automember definitions search new entries and, if they match defined LDAP search filters and regular expression conditions, add the entry to a specified group automatically. |
Type | preoperation |
Configurable Options | on |
off | Default Setting |
off | Configurable Arguments |
None for the main plug-in entry. The definition entry must specify an LDAP scope, LDAP filter, default group, and member attribute format. The optional regular expression child entry can specify inclusive and exclusive expressions and a different target group. | Dependencies |
Database | Performance-Related Information |
None. | Further Information |
4.1.9. Binary Syntax Plug-in
Binary syntax is deprecated. Use Octet String syntax instead.
Plug-in Parameter | Description |
---|---|
Plug-in ID | bin-syntax |
DN of Configuration Entry | cn=Binary Syntax,cn=plugins,cn=config |
Description | Syntax for handling binary data. |
Type | syntax |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
None | Performance-Related Information |
Do not modify the configuration of this plug-in. Red Hat recommends leaving this plug-in running at all times. | Further Information |
4.1.10. Bit String Syntax Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | bitstring-syntax |
DN of Configuration Entry | cn=Bit String Syntax,cn=plugins,cn=config |
Description | Supports bit string syntax values and related matching rules from RFC 4517. |
Type | syntax |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
None | Performance-Related Information |
Do not modify the configuration of this plug-in. Red Hat recommends leaving this plug-in running at all times. | Further Information |
4.1.11. Bitwise Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | bitwise |
DN of Configuration Entry | cn=Bitwise Plugin,cn=plugins,cn=config |
Description | Matching rule for performing bitwise operations against the LDAP server |
Type | matchingrule |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
None | Performance-Related Information |
Do not modify the configuration of this plug-in. Red Hat recommends leaving this plug-in running at all times. | Further Information |
4.1.12. Boolean Syntax Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | boolean-syntax |
DN of Configuration Entry | cn=Boolean Syntax,cn=plugins,cn=config |
Description | Supports boolean syntax values (TRUE or FALSE) and related matching rules from RFC 4517. |
Type | syntax |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
None | Performance-Related Information |
Do not modify the configuration of this plug-in. Red Hat recommends leaving this plug-in running at all times. | Further Information |
4.1.13. Case Exact String Syntax Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | ces-syntax |
DN of Configuration Entry | cn=Case Exact String Syntax,cn=plugins,cn=config |
Description | Supports case-sensitive matching or Directory String, IA5 String, and related syntaxes. This is not a case-exact syntax; this plug-in provides case-sensitive matching rules for different string syntaxes. |
Type | syntax |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
None | Performance-Related Information |
Do not modify the configuration of this plug-in. Red Hat recommends leaving this plug-in running at all times. | Further Information |
4.1.14. Case Ignore String Syntax Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | directorystring-syntax |
DN of Configuration Entry | cn=Case Ignore String Syntax,cn=plugins,cn=config |
Description | Supports case-insensitive matching rules for Directory String, IA5 String, and related syntaxes. This is not a case-insensitive syntax; this plug-in provides case-sensitive matching rules for different string syntaxes. |
Type | syntax |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
None | Performance-Related Information |
Do not modify the configuration of this plug-in. Red Hat recommends leaving this plug-in running at all times. | Further Information |
4.1.15. Chaining Database Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | chaining database |
DN of Configuration Entry | cn=Chaining database,cn=plugins,cn=config |
Description | Enables back end databases to be linked |
Type | database |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
None | Performance-Related Information |
There are many performance related tuning parameters involved with the chaining database. See the "Maintaining Database Links" section in the Red Hat Directory Server Administration Guide. | Further Information |
4.1.16. Class of Service Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | cos |
DN of Configuration Entry | cn=Class of Service,cn=plugins,cn=config |
Description | Allows for sharing of attributes between entries |
Type | object |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
* Type: Database * Named: State Change Plug-in * Named: Views Plug-in | Performance-Related Information |
Do not modify the configuration of this plug-in. Leave this plug-in running at all times. | Further Information |
4.1.17. Content Synchronization Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | content-sync-plugin |
DN of Configuration Entry | cn=Content Synchronization,cn=plugins,cn=config |
Description |
Enables support for the |
Type | object |
Configurable Options | on |
off | Default Setting |
off | Configurable Arguments |
None | Dependencies |
Retro Changelog Plug-in | Performance-Related Information |
If you know which back end or subtree clients access to synchronize data, limit the scope of the | Further Information |
4.1.18. Country String Syntax Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | countrystring-syntax |
DN of Configuration Entry | cn=Country String Syntax,cn=plugins,cn=config |
Description | Supports country naming syntax values and related matching rules from RFC 4517. |
Type | syntax |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
None | Performance-Related Information |
Do not modify the configuration of this plug-in. Red Hat recommends leaving this plug-in running at all times. | Further Information |
4.1.19. Delivery Method Syntax Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | delivery-syntax |
DN of Configuration Entry | cn=Delivery Method Syntax,cn=plugins,cn=config |
Description | Supports values that are lists of preferred deliver methods and related matching rules from RFC 4517. |
Type | syntax |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
None | Performance-Related Information |
Do not modify the configuration of this plug-in. Red Hat recommends leaving this plug-in running at all times. | Further Information |
4.1.20. deref Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | Dereference |
DN of Configuration Entry | cn=deref,cn=plugins,cn=config |
Description | For dereference controls in directory searches |
Type | preoperation |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
Database | Performance-Related Information |
Do not modify the configuration of this plug-in. Red Hat recommends leaving this plug-in running at all times. | Further Information |
4.1.21. Distinguished Name Syntax Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | dn-syntax |
DN of Configuration Entry | cn=Distinguished Name Syntax,cn=plugins,cn=config |
Description | Supports DN value syntaxes and related matching rules from RFC 4517. |
Type | syntax |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
None | Performance-Related Information |
Do not modify the configuration of this plug-in. Red Hat recommends leaving this plug-in running at all times. | Further Information |
4.1.22. Distributed Numeric Assignment Plug-in
Plug-in Information | Description |
---|---|
Plug-in ID | Distributed Numeric Assignment |
Configuration Entry DN | cn=Distributed Numeric Assignment Plugin,cn=plugins,cn=config |
Description | Distributed Numeric Assignment plugin |
Type | preoperation |
Configurable Options | on |
off | Default Setting |
off | Configurable Arguments |
Dependencies | |
Database | Performance-Related Information |
None | Further Information |
4.1.23. Enhanced Guide Syntax Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | enhancedguide-syntax |
DN of Configuration Entry | cn=Enhanced Guide Syntax,cn=plugins,cn=config |
Description | Supports syntaxes and related matching rules for creating complex criteria, based on attributes and filters, to build searches; from RFC 4517. |
Type | syntax |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
None | Performance-Related Information |
Do not modify the configuration of this plug-in. Red Hat recommends leaving this plug-in running at all times. | Further Information |
4.1.24. Facsimile Telephone Number Syntax Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | facsimile-syntax |
DN of Configuration Entry | cn=Facsimile Telephone Number Syntax,cn=plugins,cn=config |
Description | Supports syntaxes and related matching rules for fax numbers; from RFC 4517. |
Type | syntax |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
None | Performance-Related Information |
Do not modify the configuration of this plug-in. Red Hat recommends leaving this plug-in running at all times. | Further Information |
4.1.25. Fax Syntax Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | fax-syntax |
DN of Configuration Entry | cn=Fax Syntax,cn=plugins,cn=config |
Description | Supports syntaxes and related matching rules for storing images of faxed objects; from RFC 4517. |
Type | syntax |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
None | Performance-Related Information |
Do not modify the configuration of this plug-in. Red Hat recommends leaving this plug-in running at all times. | Further Information |
4.1.26. Generalized Time Syntax Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | time-syntax |
DN of Configuration Entry | cn=Generalized Time Syntax,cn=plugins,cn=config |
Description | Supports syntaxes and related matching rules for dealing with dates, times and time zones; from RFC 4517. |
Type | syntax |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
None | Performance-Related Information |
Do not modify the configuration of this plug-in. Red Hat recommends leaving this plug-in running at all times. | Further Information |
4.1.27. Guide Syntax Plug-in
This syntax is deprecated. Use Enhanced Guide syntax instead.
Plug-in Parameter | Description |
---|---|
Plug-in ID | guide-syntax |
DN of Configuration Entry | cn=Guide Syntax,cn=plugins,cn=config |
Description | Syntax for creating complex criteria, based on attributes and filters, to build searches |
Type | syntax |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
None | Performance-Related Information |
Do not modify the configuration of this plug-in. Red Hat recommends leaving this plug-in running at all times. | Further Information |
4.1.28. HTTP Client Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | http-client |
DN of Configuration Entry | cn=HTTP Client,cn=plugins,cn=config |
Description | HTTP client plug-in |
Type | preoperation |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
Database | Performance-Related Information |
Further Information |
4.1.29. Integer Syntax Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | int-syntax |
DN of Configuration Entry | cn=Integer Syntax,cn=plugins,cn=config |
Description | Supports integer syntaxes and related matching rules from RFC 4517. |
Type | syntax |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
None | Performance-Related Information |
Do not modify the configuration of this plug-in. Red Hat recommends leaving this plug-in running at all times. | Further Information |
4.1.30. Internationalization Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | orderingrule |
DN of Configuration Entry | cn=Internationalization Plugin,cn=plugins,cn=config |
Description | Enables internationalized strings to be ordered in the directory |
Type | matchingrule |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
The Internationalization Plug-in has one argument, which must not be modified, which specifies the location of the | Dependencies |
None | Performance-Related Information |
Do not modify the configuration of this plug-in. Red Hat recommends leaving this plug-in running at all times. | Further Information |
4.1.31. JPEG Syntax Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | jpeg-syntax |
DN of Configuration Entry | cn=JPEG Syntax,cn=plugins,cn=config |
Description | Supports syntaxes and related matching rules for JPEG image data; from RFC 4517. |
Type | syntax |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
None | Performance-Related Information |
Do not modify the configuration of this plug-in. Red Hat recommends leaving this plug-in running at all times. | Further Information |
4.1.32. ldbm database Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | ldbm-backend |
DN of Configuration Entry | cn=ldbm database,cn=plugins,cn=config |
Description | Implements local databases |
Type | database |
Configurable Options | |
Default Setting | on |
Configurable Arguments | None |
Dependencies | * Syntax * matchingRule |
Performance-Related Information | See Section 4.4, “Database Plug-in Attributes” for further information on database configuration. |
Further Information | See the "Configuring Directory Databases" chapter in the Red Hat Directory Server Administration Guide. |
4.1.33. Linked Attributes Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | Linked Attributes |
DN of Configuration Entry | cn=Linked Attributes,cn=plugins,cn=config |
Description |
Container entry for linked-managed attribute configuration entries. Each configuration entry under the container links one attribute to another, so that when one entry is updated (such as a manager entry), then any entry associated with that entry (such as a custom |
Type | preoperation |
Configurable Options | on |
off | Default Setting |
off | Configurable Arguments |
None for the main plug-in entry. Each plug-in instance has three possible attributes: * linkType, which sets the primary attribute for the plug-in to monitor * managedType, which sets the attribute which will be managed dynamically by the plug-in whenever the attribute in linkType is modified * linkScope, which restricts the plug-in activity to a specific subtree within the directory tree | Dependencies |
Database | Performance-Related Information |
Any attribute set in linkType must only allow values in a DN format. Any attribute set in managedType must be multi-valued. | Further Information |
4.1.34. Managed Entries Plug-in
Plug-in Information | Description |
---|---|
Plug-in ID | Managed Entries |
Configuration Entry DN | cn=Managed Entries,cn=plugins,cn=config |
Description | Container entry for automatically generated directory entries. Each configuration entry defines a target subtree and a template entry. When a matching entry in the target subtree is created, then the plug-in automatically creates a new, related entry based on the template. |
Type | preoperation |
Configurable Options | on |
off | Default Setting |
off | Configurable Arguments |
None for the main plug-in entry. Each plug-in instance has four possible attributes: * originScope, which sets the search base * originFilter, which sets the search base for matching entries * managedScope, which sets the subtree under which to create new managed entries * managedTemplate, which is the template entry used to create the managed entries | Dependencies |
Database | Performance-Related Information |
None | Further Information |
4.1.35. MemberOf Plug-in
Plug-in Information | Description |
---|---|
Plug-in ID | memberOf |
Configuration Entry DN | cn=MemberOf Plugin,cn=plugins,cn=config |
Description |
Manages the |
Type | postoperation |
Configurable Options | on |
off | Default Setting |
off | Configurable Arguments |
*
* | Dependencies |
Database | Performance-Related Information |
None | Further Information |
4.1.36. Multi-master Replication Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | replication-multimaster |
DN of Configuration Entry | cn=Multimaster Replication plugin,cn=plugins,cn=config |
Description | Enables replication between two current Directory Servers |
Type | object |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
* Named: ldbm database * Named: DES * Named: Class of Service | Performance-Related Information |
Further Information |
4.1.37. Name and Optional UID Syntax Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | nameoptuid-syntax |
DN of Configuration Entry | cn=Name And Optional UID Syntax,cn=plugins,cn=config |
Description | Supports syntaxes and related matching rules to store and search for a DN with an optional unique ID; from RFC 4517. |
Type | syntax |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
None | Performance-Related Information |
Do not modify the configuration of this plug-in. Red Hat recommends leaving this plug-in running at all times. | Further Information |
4.1.38. Numeric String Syntax Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | numstr-syntax |
DN of Configuration Entry | cn=Numeric String Syntax,cn=plugins,cn=config |
Description | Supports syntaxes and related matching rules for strings of numbers and spaces; from RFC 4517. |
Type | syntax |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
None | Performance-Related Information |
Do not modify the configuration of this plug-in. Red Hat recommends leaving this plug-in running at all times. | Further Information |
4.1.39. Octet String Syntax Plug-in
Use the Octet String syntax instead of Binary, which is deprecated.
Plug-in Parameter | Description |
---|---|
Plug-in ID | octetstring-syntax |
DN of Configuration Entry | cn=Octet String Syntax,cn=plugins,cn=config |
Description | Supports octet string syntaxes and related matching rules from RFC 4517. |
Type | syntax |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
None | Performance-Related Information |
Do not modify the configuration of this plug-in. Red Hat recommends leaving this plug-in running at all times. | Further Information |
4.1.40. OID Syntax Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | oid-syntax |
DN of Configuration Entry | cn=OID Syntax,cn=plugins,cn=config |
Description | Supports object identifier (OID) syntaxes and related matching rules from RFC 4517. |
Type | syntax |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
None | Performance-Related Information |
Do not modify the configuration of this plug-in. Red Hat recommends leaving this plug-in running at all times. | Further Information |
4.1.41. PAM Pass Through Auth Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | pam_passthruauth |
DN of Configuration Entry | cn=PAM Pass Through Auth,cn=plugins,cn=config |
Description | Enables pass-through authentication for PAM, meaning that a PAM service can use the Directory Server as its user authentication store. |
Type | preoperation |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
Database | Performance-Related Information |
Further Information |
4.1.42. Pass Through Authentication Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | passthruauth |
DN of Configuration Entry | cn=Pass Through Authentication,cn=plugins,cn=config |
Description | Enables pass-through authentication, the mechanism which allows one directory to consult another to authenticate bind requests. |
Type | preoperation |
Configurable Options | on |
off | Default Setting |
off | Configurable Arguments |
ldap://example.com:389/o=example | Dependencies |
Database | Performance-Related Information |
Pass-through authentication slows down bind requests a little because they have to make an extra hop to the remote server. See the "Using Pass-through Authentication" chapter in the Red Hat Directory Server Administration Guide. | Further Information |
4.1.43. Password Storage Schemes
Directory Server implements the password storage schemes as plug-ins. However, the cn=Password Storage Schemes,cn=plugins,cn=config
entry itself is just a container, not a plug-in entry. All password storage scheme plug-ins are stored as a subentry of this container.
To display all password storage schemes plug-ins, enter:
# ldapsearch -D "cn=Directory Manager" -W -p 389 -h server.example.com -x \ -b "cn=Password Storage Schemes,cn=plugins,cn=config" -s sub "(objectclass=*)" dn
Red Hat recommends not disabling the password scheme plug-ins nor to change the configurations of the plug-ins to prevent unpredictable authentication behavior.
Strong Password Storage Schemes
Red Hat recommends using only the following strong password storage schemes (strongest first):
PBKDF2_SHA256
(default)The password-based key derivation function 2 (PBKDF2) was designed to expend resources to counter brute force attacks. PBKDF2 supports a variable number of iterations to apply the hashing algorithm. Higher iterations improve security but require more hardware resources. In Directory Server, the
PBKDF2_SHA256
scheme is implemented using 30,000 iterations to apply the SHA256 algorithm. This value is hard-coded and will be increased in future versions of Directory Server without requiring interaction by an administrator.NoteThe network security service (NSS) database in Red Hat Enterprise Linux 6 does not support PBKDF2. Therefore you cannot use this password scheme in a replication topology with Directory Server 9.
SSHA512
The salted secure hashing algorithm (SSHA) implements an enhanced version of the secure hashing algorithm (SHA), that uses a randomly generated salt to increase the security of the hashed password.
SSHA512
implements the hashing algorithm using 512 bits.
Weak Password Storage Schemes
Besides the recommended strong password storage schemes, Directory Server supports the following weak schemes for backward compatibility:
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[a]
Directory Server only supports authentication using this scheme. You can no longer use it to encrypt passwords.
[b]
160 bit
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Only continue using a weak scheme over a short time frame, as it increases security risks.
4.1.44. Posix Winsync API Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | posix-winsync-plugin |
DN of Configuration Entry | cn=Posix Winsync API,cn=plugins,cn=config |
Description | Enables and configures Windows synchronization for Posix attributes set on Active Directory user and group entries. |
Type | preoperation |
Configurable Arguments | * on |
off * memberUID mapping (groups) * converting and sorting memberUID values in lower case (groups) * memberOf fix-up tasks with sync operations * use Windows 2003 Posix schema | Default Setting |
off | Configurable Arguments |
None | Dependencies |
4.1.45. Postal Address String Syntax Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | postaladdress-syntax |
DN of Configuration Entry | cn=Postal Address Syntax,cn=plugins,cn=config |
Description | Supports postal address syntaxes and related matching rules from RFC 4517. |
Type | syntax |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
None | Performance-Related Information |
Do not modify the configuration of this plug-in. Red Hat recommends leaving this plug-in running at all times. | Further Information |
4.1.46. Printable String Syntax Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | printablestring-syntax |
DN of Configuration Entry | cn=Printable String Syntax,cn=plugins,cn=config |
Description | Supports syntaxes and matching rules for alphanumeric and select punctuation strings (for strings which conform to printable strings as defined in RFC 4517). |
Type | syntax |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
None | Performance-Related Information |
Do not modify the configuration of this plug-in. Red Hat recommends leaving this plug-in running at all times. | Further Information |
4.1.47. Referential Integrity Postoperation Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | referint |
DN of Configuration Entry | cn=Referential Integrity Postoperation,cn=plugins,cn=config |
Description | Enables the server to ensure referential integrity |
Type | postoperation |
Configurable Options | All configuration and on |
off | Default Setting |
off | Configurable Arguments |
When enabled, the post-operation Referential Integrity Plug-in performs integrity updates on the | Dependencies |
Database | Performance-Related Information |
The Referential Integrity Plug-in should be enabled only on one supplier in a multi-supplier replication environment to avoid conflict resolution loops. When enabling the plug-in on chained servers, be sure to analyze the performance resource and time needs as well as integrity needs; integrity checks can be time consuming and demanding on memory and CPU. All attributes specified must be indexed for both presence and equality. | Further Information |
4.1.48. Retro Changelog Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | retrocl |
DN of Configuration Entry | cn=Retro Changelog Plugin,cn=plugins,cn=config |
Description |
Used by LDAP clients for maintaining application compatibility with Directory Server 4.x versions. Maintains a log of all changes occurring in the Directory Server. The retro changelog offers the same functionality as the changelog in the 4.x versions of Directory Server. This plug-in exposes the |
Type | object |
Configurable Options | on |
off | Default Setting |
off | Configurable Arguments |
See Section 4.16, “Retro Changelog Plug-in Attributes” for further information on the two configuration attributes for this plug-in. | Dependencies |
* Type: Database * Named: Class of Service | Performance-Related Information |
May slow down Directory Server update performance. | Further Information |
4.1.49. Roles Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | roles |
DN of Configuration Entry | cn=Roles Plugin,cn=plugins,cn=config |
Description | Enables the use of roles in the Directory Server |
Type | object |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
* Type: Database * Named: State Change Plug-in * Named: Views Plug-in | Performance-Related Information |
Do not modify the configuration of this plug-in. Red Hat recommends leaving this plug-in running at all times. | Further Information |
4.1.50. RootDN Access Control Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | rootdn-access-control |
DN of Configuration Entry | cn=RootDN Access Control,cn=plugins,cn=config |
Description | Enables and configures access controls to use for the root DN entry. |
Type | internalpreoperation |
Configurable Options | on |
off | Default Setting |
off | Configurable Attributes |
* rootdn-open-time and rootdn-close-time for time-based access controls * rootdn-days-allowed for day-based access controls * rootdn-allow-host, rootdn-deny-host, rootdn-allow-ip, and rootdn-deny-ip for host-based access controls | Dependencies |
None | Further Information |
4.1.51. Schema Reload Plug-in
Plug-in Information | Description |
---|---|
Plug-in ID | schemareload |
Configuration Entry DN | cn=Schema Reload,cn=plugins,cn=config |
Description | Task plug-in to reload schema files |
Type | object |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
None | Performance-Related Information |
Further Information |
4.1.52. Space Insensitive String Syntax Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | none |
DN of Configuration Entry | cn=Space Insensitive String Syntax,cn=plugins,cn=config |
Description | Syntax for handling space-insensitive values |
Type | syntax |
Configurable Options | on |
off | Default Setting |
off | Configurable Arguments |
None | Dependencies |
None | Performance-Related Information |
Do not modify the configuration of this plug-in. Red Hat recommends leaving this plug-in running at all times. | Further Information |
4.1.53. State Change Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | statechange |
DN of Configuration Entry | cn=State Change Plugin,cn=plugins,cn=config |
Description | Enables state-change-notification service |
Type | postoperation |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
None | Performance-Related Information |
Further Information |
4.1.54. Syntax Validation Task Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | none |
DN of Configuration Entry | cn=Syntax Validation Task,cn=plugins,cn=config |
Description | Enables syntax validation for attribute values |
Type | object |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
None | Performance-Related Information |
Further Information |
4.1.55. Telephone Syntax Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | tele-syntax |
DN of Configuration Entry | cn=Telephone Syntax,cn=plugins,cn=config |
Description | Supports telephone number syntaxes and related matching rules from RFC 4517. |
Type | syntax |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
None | Performance-Related Information |
Do not modify the configuration of this plug-in. Red Hat recommends leaving this plug-in running at all times. | Further Information |
4.1.56. Teletex Terminal Identifier Syntax Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | teletextermid-syntax |
DN of Configuration Entry | cn=Teletex Terminal Identifier Syntax,cn=plugins,cn=config |
Description | Supports international telephone number syntaxes and related matching rules from RFC 4517. |
Type | syntax |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
None | Performance-Related Information |
Do not modify the configuration of this plug-in. Red Hat recommends leaving this plug-in running at all times. | Further Information |
4.1.57. Telex Number Syntax Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | telex-syntax |
DN of Configuration Entry | cn=Telex Number Syntax,cn=plugins,cn=config |
Description | Supports syntaxes and related matching rules for the telex number, country code, and answerback code of a telex terminal; from RFC 4517. |
Type | syntax |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
None | Performance-Related Information |
Do not modify the configuration of this plug-in. Red Hat recommends leaving this plug-in running at all times. | Further Information |
4.1.58. URI Syntax Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | none |
DN of Configuration Entry | cn=URI Syntax,cn=plugins,cn=config |
Description | Supports syntaxes and related matching rules for unique resource identifiers (URIs), including unique resource locators (URLs); from RFC 4517. |
Type | syntax |
Configurable Options | on |
off | Default Setting |
off | Configurable Arguments |
None | Dependencies |
None | Performance-Related Information |
Do not modify the configuration of this plug-in. If enabled, Red Hat recommends leaving this plug-in running at all times. | Further Information |
4.1.59. USN Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | USN |
DN of Configuration Entry | cn=USN,cn=plugins,cn=config |
Description | Sets an update sequence number (USN) on an entry, for every entry in the directory, whenever there is a modification, including adding and deleting entries and modifying attribute values. |
Type | object |
Configurable Options | on |
off | Default Setting |
off | Configurable Arguments |
None | Dependencies |
Database | Performance-Related Information |
For replication, it is recommended that the | Further Information |
4.1.60. Views Plug-in
Plug-in Parameter | Description |
---|---|
Plug-in ID | views |
DN of Configuration Entry | cn=Views,cn=plugins,cn=config |
Description | Enables the use of views in the Directory Server databases. |
Type | object |
Configurable Options | on |
off | Default Setting |
on | Configurable Arguments |
None | Dependencies |
* Type: Database * Named: State Change Plug-in | Performance-Related Information |
Do not modify the configuration of this plug-in. Red Hat recommends leaving this plug-in running at all times. | Further Information |
4.2. List of Attributes Common to All Plug-ins
This list provides a brief attribute description, the entry DN, valid range, default value, syntax, and an example for each attribute.
4.2.1. nsslapdPlugin (Object Class)
Each Directory Server plug-in belongs to the nsslapdPlugin
object class.
This object class is defined in Directory Server.
Superior Class
top
OID
2.16.840.1.113730.3.2.41
Table 4.1. Required Attributes
Attribute | Definition |
---|---|
objectClass | Gives the object classes assigned to the entry. |
cn | Gives the common name of the entry. |
Identifies the plugin library name (without the library suffix). | |
Identifies an initialization function of the plugin. | |
Identifies the type of plugin. | |
Identifies the plugin ID. | |
Identifies the version of plugin. | |
Identifies the vendor of plugin. | |
Identifies the description of the plugin. | |
Identifies whether or not the plugin is enabled. | |
Sets the priority for the plug-in in the execution order. |
4.2.2. nsslapd-logAccess
This attribute enables you to log search operations run by the plug-in to the file set in the nsslapd-accesslog
parameter in cn=config
.
Plug-in Parameter | Description |
---|---|
Entry DN | cn=plug-in name,cn=plugins,cn=config |
Valid Values | on | off |
Default Value | off |
Syntax | DirectoryString |
Example | nsslapd-logAccess: Off |
4.2.3. nsslapd-logAudit
This attribute enables you to log and audit modifications to the database originated from the plug-in.
Successful modification events are logged in the audit log, if the nsslapd-auditlog-logging-enabled
parameter is enabled in cn=config
. To log failed modification database operations by a plug-in, enable the nsslapd-auditfaillog-logging-enabled
attribute in cn=config
.
Plug-in Parameter | Description |
---|---|
Entry DN | cn=plug-in name,cn=plugins,cn=config |
Valid Values | on | off |
Default Value | off |
Syntax | DirectoryString |
Example | nsslapd-logAudit: Off |
4.2.4. nsslapd-pluginDescription
This attribute provides a description of the plug-in.
Plug-in Parameter | Description |
---|---|
Entry DN | cn=plug-in name,cn=plugins,cn=config |
Valid Values | |
Default Value | None |
Syntax | DirectoryString |
Example | nsslapd-pluginDescription: acl access check plug-in |
4.2.5. nsslapd-pluginEnabled
This attribute specifies whether the plug-in is enabled. This attribute can be changed over protocol but will only take effect when the server is next restarted.
Plug-in Parameter | Description |
---|---|
Entry DN | cn=plug-in name,cn=plugins,cn=config |
Valid Values | on | off |
Default Value | on |
Syntax | DirectoryString |
Example | nsslapd-pluginEnabled: on |
4.2.6. nsslapd-pluginId
This attribute specifies the plug-in ID.
Plug-in Parameter | Description |
---|---|
Entry DN | cn=plug-in name,cn=plugins,cn=config |
Valid Values | Any valid plug-in ID |
Default Value | None |
Syntax | DirectoryString |
Example | nsslapd-pluginId: chaining database |
4.2.7. nsslapd-pluginInitfunc
This attribute specifies the plug-in function to be initiated.
Plug-in Parameter | Description |
---|---|
Entry DN | cn=plug-in name,cn=plugins,cn=config |
Valid Values | Any valid plug-in function |
Default Value | None |
Syntax | DirectoryString |
Example | nsslapd-pluginInitfunc: NS7bitAttr_Init |
4.2.8. nsslapd-pluginPath
This attribute specifies the full path to the plug-in.
Plug-in Parameter | Description |
---|---|
Entry DN | cn=plug-in name,cn=plugins,cn=config |
Valid Values | Any valid path |
Default Value | None |
Syntax | DirectoryString |
Example | nsslapd-pluginPath: uid-plugin |
4.2.9. nsslapd-pluginPrecedence
This attribute sets the precedence or priority for the execution order of a plug-in. Precedence defines the execution order of plug-ins, which allows more complex environments or interactions since it can enable a plug-in to wait for a completed operation before being executed. This is more important for pre-operation and post-operation plug-ins.
Plug-ins with a value of 1 have the highest priority and are run first; plug-ins with a value of 99 have the lowest priority. The default is 50.
Plug-in Parameter | Description |
---|---|
Entry DN | cn=plug-in name,cn=plugins,cn=config |
Valid Values | 1 to 99 |
Default Value | 50 |
Syntax | Integer |
Example | nsslapd-pluginPrecedence: 3 |
4.2.10. nsslapd-pluginType
This attribute specifies the plug-in type. See Section 4.3.5, “nsslapd-plugin-depends-on-type” for further information.
Plug-in Parameter | Description |
---|---|
Entry DN | cn=plug-in name,cn=plugins,cn=config |
Valid Values | Any valid plug-in type |
Default Value | None |
Syntax | DirectoryString |
Example | nsslapd-pluginType: preoperation |
4.2.11. nsslapd-pluginVendor
This attribute specifies the vendor of the plug-in.
Plug-in Parameter | Description |
---|---|
Entry DN | cn=plug-in name,cn=plugins,cn=config |
Valid Values | Any approved plug-in vendor |
Default Value | Red Hat, Inc. |
Syntax | DirectoryString |
Example | nsslapd-pluginVendor: Red Hat, Inc. |
4.2.12. nsslapd-pluginVersion
This attribute specifies the plug-in version.
Plug-in Parameter | Description |
---|---|
Entry DN | cn=plug-in name,cn=plugins,cn=config |
Valid Values | Any valid plug-in version |
Default Value | Product version number |
Syntax | DirectoryString |
Example | nsslapd-pluginVersion: 11.3 |
4.3. Attributes Allowed by Certain Plug-ins
4.3.1. nsslapd-dynamic-plugins
Directory Server supports dynamic plug-ins that can be enabled without restarting the server. The nsslapd-dynamic-plugins
attribute specifies whether the server is configured to allow for dynamic plug-ins. By default, dynamic plug-ins are disabled.
Some plug-ins cannot be configured as dynamic, and they require the server to be restarted.
Plug-in Parameter | Description |
---|---|
Entry DN | cn=config |
Valid Values | on | off |
Default Value | off |
Syntax | DirectoryString |
Example | nsslapd-dynamic-plugins: on |
4.3.2. nsslapd-pluginConfigArea
Some plug-in entries are container entries, and multiple instances of the plug-in are created beneath this container in cn=plugins,cn=config
. However, the cn=plugins,cn=config
is not replicated, which means that the plug-in configurations beneath those container entries must be configured manually, in some way, on every Directory Server instance.
The nsslapd-pluginConfigArea
attribute points to another container entry, in the main database area, which contains the plug-in instance entries. This container entry can be in a replicated database, which allows the plug-in configuration to be replicated.
Plug-in Parameter | Description |
---|---|
Entry DN | cn=plug-in name,cn=plugins,cn=config |
Valid Values | Any valid DN |
Default Value | |
Syntax | DN |
Example | nsslapd-pluginConfigArea: cn=managed entries container,ou=containers,dc=example,dc=com |
4.3.3. nsslapd-pluginLoadNow
This attribute specifies whether to load all of the symbols used by a plug-in immediately (true
), as well as all symbols references by those symbols, or to load the symbol the first time it is used (false
).
Plug-in Parameter | Description |
---|---|
Entry DN | cn=plug-in name,cn=plugins,cn=config |
Valid Values | true | false |
Default Value | false |
Syntax | DirectoryString |
Example | nsslapd-pluginLoadNow: false |
4.3.4. nsslapd-pluginLoadGlobal
This attribute specifies whether the symbols in dependent libraries are made visible locally (false
) or to the executable and to all shared objects (true
).
Plug-in Parameter | Description |
---|---|
Entry DN | cn=plug-in name,cn=plugins,cn=config |
Valid Values | true | false |
Default Value | false |
Syntax | DirectoryString |
Example | nsslapd-pluginLoadGlobal: false |
4.3.5. nsslapd-plugin-depends-on-type
Multi-valued attribute used to ensure that plug-ins are called by the server in the correct order. Takes a value which corresponds to the type number of a plug-in, contained in the attribute nsslapd-pluginType
. See Section 4.2.10, “nsslapd-pluginType” for further information. All plug-ins with a type value which matches one of the values in the following valid range will be started by the server prior to this plug-in. The following postoperation Referential Integrity Plug-in example shows that the database plug-in will be started prior to the postoperation Referential Integrity Plug-in.
Plug-in Parameter | Description |
---|---|
Entry DN | cn=referential integrity postoperation,cn=plugins,cn=config |
Valid Values | database |
Default Value | |
Syntax | DirectoryString |
Example | nsslapd-plugin-depends-on-type: database |
4.3.6. nsslapd-plugin-depends-on-named
Multi-valued attribute used to ensure that plug-ins are called by the server in the correct order. Takes a value which corresponds to the cn
value of a plug-in. The plug-in with a cn
value matching one of the following values will be started by the server prior to this plug-in. If the plug-in does not exist, the server fails to start. The following postoperation Referential Integrity Plug-in example shows that the Views plug-in is started before Roles. If Views is missing, the server is not going to start.
Plug-in Parameter | Description |
---|---|
Entry DN | cn=referential integrity postoperation,cn=plugins,cn=config |
Valid Values | Class of Service |
Default Value | |
Syntax | DirectoryString |
Example | * nsslapd-plugin-depends-on-named: Views * nsslapd-pluginId: roles |
4.4. Database Plug-in Attributes
The database plug-in is also organized in an information tree, as shown in Figure 4.1, “Database Plug-in”.
Figure 4.1. Database Plug-in

All plug-in technology used by the database instances is stored in the cn=ldbm database
plug-in node. This section presents the additional attribute information for each of the nodes in bold in the cn=ldbm database,cn=plugins,cn=config
information tree.
4.4.1. Database Attributes under cn=config,cn=ldbm database,cn=plugins,cn=config
This section covers global configuration attributes common to all instances are stored in the cn=config,cn=ldbm database,cn=plugins,cn=config
tree node.
4.4.1.1. nsslapd-backend-implement
The nsslapd-backend-implement
parameter defines the database back end Directory Server uses.
Directory Server currently only supports the Berkeley Database (BDB). Therefore, you cannot set this parameter to a different value.
Parameter | Description |
---|---|
Entry DN | cn=bdb,cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Values | bdb |
Default Value | bdb |
Syntax | Directory String |
Example | nsslapd-backend-implement: bdb |
4.4.1.2. nsslapd-backend-opt-level
This parameter can trigger experimental code to improve write performance.
Possible values:
-
0
: Disables the parameter. -
1
: The replication update vector is not written to the database during the transaction -
2
: Changes the order of taking the back end lock and starts the transaction -
4
: Moves code out of the transaction.
All parameters can be combined. For example 7
enables all optimisation features.
This parameter is experimental. Never change its value unless you are specifically told to do so by the Red Hat support.
Parameter | Description |
---|---|
Entry DN | cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Values | 0 | 1 | 2 | 4 |
Default Value | 0 |
Syntax | Integer |
Example | nsslapd-backend-opt-level: 0 |
4.4.1.3. nsslapd-directory
This attribute specifies absolute path to database instance. If the database instance is manually created then this attribute must be included, something which is set by default (and modifiable) in the Directory Server Console. Once the database instance is created, do not modify this path as any changes risk preventing the server from accessing data.
Parameter | Description |
---|---|
Entry DN | cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Values | Any valid absolute path to the database instance |
Default Value | |
Syntax | DirectoryString |
Example | nsslapd-directory: /var/lib/dirsrv/slapd-instance/db |
4.4.1.4. nsslapd-exclude-from-export
This attribute contains a space-separated list of names of attributes to exclude from an entry when a database is exported. This mainly is used for some configuration and operational attributes which are specific to a server instance.
Do not remove any of the default values for this attribute, since that may affect server performance.
Parameter | Description |
---|---|
Entry DN | cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Values | Any valid attribute |
Default Value | entrydn entryid dncomp parentid numSubordinates entryusn |
Syntax | DirectoryString |
Example | nsslapd-exclude-from-export: entrydn entryid dncomp parentid numSubordinates entryusn |
4.4.1.5. nsslapd-db-compactdb-time
The nsslapd-db-compactdb-time
attribute sets the time of the day when Directory Server compacts all databases and their replication changelogs. The compaction task runs after the compaction interval (nsslapd-db-compactdb-interval
) has been exceeded.
You do not have to restart the server for this setting to take effect.
Parameter | Description |
---|---|
Entry DN | cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Values | HH:MM. Time is set in 24-hour format |
Default Value | 23:59 |
Syntax | DirectoryString |
Example | nsslapd-db-compactdb-time: 23:59 |
4.4.1.6. nsslapd-db-compactdb-interval
The nsslapd-db-compactdb-interval
attribute defines the interval in seconds when Directory Server compacts the databases and replication changelogs. The compact operation returns the unused pages to the file system and the database file size shrinks. Note that compacting the database is resource-intensive and should not be done too often.
You do not have to restart the server for this setting to take effect.
Parameter | Description |
---|---|
Entry DN | cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Values | 0 (no compaction) to 2147483647 second |
Default Value | 2592000 (30 days) |
Syntax | Integer |
Example | nsslapd-db-compactdb-interval: 2592000 |
4.4.1.7. nsslapd-db-transaction-wait
If you enable the nsslapd-db-transaction-wait
parameter, Directory Server does not start the transaction and waits until lock resources are available.
Parameter | Description |
---|---|
Entry DN | cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Values | on | off |
Default Value | off |
Syntax | DirectoryString |
Example | nsslapd-db-transaction-wait: off |
4.4.1.8. nsslapd-db-private-import-mem
The nsslapd-db-private-import-mem
parameter manages whether or not Directory Server uses private memory for allocation of regions and mutexes for a database import.
Parameter | Description |
---|---|
Entry DN | cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Values | on | off |
Default Value | on |
Syntax | DirectoryString |
Example | nsslapd-db-private-import-mem: on |
4.4.1.9. nsslapd-db-deadlock-policy
The nsslapd-db-deadlock-policy
parameter sets the libdb
library-internal deadlock policy.
Only change this parameter if instructed by Red Hat Support.
Parameter | Description |
---|---|
Entry DN | cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Values | 0-9 |
Default Value | 0 |
Syntax | DirectoryString |
Example | nsslapd-db-deadlock-policy: 9 |
4.4.1.10. nsslapd-idl-switch
The nsslapd-idl-switch
parameter sets the IDL format Directory Server uses. Note that Red Hat no longer supports the old IDL format.
Parameter | Description |
---|---|
Entry DN | cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Values | new | old |
Default Value | new |
Syntax | Directory String |
Example | nsslapd-idl-switch: new |
4.4.1.11. nsslapd-idlistscanlimit
This performance-related attribute, present by default, specifies the number of entry IDs that are searched during a search operation. Attempting to set a value that is not a number or is too big for a 32-bit signed integer returns an LDAP_UNWILLING_TO_PERFORM
error message, with additional error information explaining the problem. It is advisable to keep the default value to improve search performance.
For further details, see the corresponding sections in the:
This parameter can be changed while the server is running, and the new value will affect subsequent searches.
The corresponding user-level attribute is nsIDListScanLimit
.
Parameter | Description |
---|---|
Entry DN | cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Range | 100 to the maximum 32-bit integer value (2147483647) entry IDs |
Default Value | 4000 |
Syntax | Integer |
Example | nsslapd-idlistscanlimit: 4000 |
4.4.1.12. nsslapd-lookthroughlimit
This performance-related attribute specifies the maximum number of entries that the Directory Server will check when examining candidate entries in response to a search request. The Directory Manager DN, however, is, by default, unlimited and overrides any other settings specified here. It is worth noting that binder-based resource limits work for this limit, which means that if a value for the operational attribute nsLookThroughLimit
is present in the entry as which a user binds, the default limit will be overridden. Attempting to set a value that is not a number or is too big for a 32-bit signed integer returns an LDAP_UNWILLING_TO_PERFORM
error message with additional error information explaining the problem.
Parameter | Description |
---|---|
Entry DN | cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Range | -1 to maximum 32-bit integer in entries (where -1 is unlimited) |
Default Value | 5000 |
Syntax | Integer |
Example | nsslapd-lookthroughlimit: 5000 |
4.4.1.13. nsslapd-mode
This attribute specifies the permissions used for newly created index files.
Parameter | Description |
---|---|
Entry DN | cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Values |
Any four-digit octal number. However, mode |
Default Value | 600 |
Syntax | Integer |
Example | nsslapd-mode: 0600 |
4.4.1.14. nsslapd-pagedidlistscanlimit
This performance-related attribute specifies the number of entry IDs that are searched, specifically, for a search operation using the simple paged results control.
This attribute works the same as the nsslapd-idlistscanlimit
attribute, except that it only applies to searches with the simple paged results control.
If this attribute is not present or is set to zero, then the nsslapd-idlistscanlimit
is used to paged searches as well as non-paged searches.
The corresponding user-level attribute is nsPagedIDListScanLimit
.
Parameter | Description |
---|---|
Entry DN | cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Range | -1 to maximum 32-bit integer in entries (where -1 is unlimited) |
Default Value | 0 |
Syntax | Integer |
Example | nsslapd-pagedidlistscanlimit: 5000 |
4.4.1.15. nsslapd-pagedlookthroughlimit
This performance-related attribute specifies the maximum number of entries that the Directory Server will check when examining candidate entries for a search which uses the simple paged results control.
This attribute works the same as the nsslapd-lookthroughlimit
attribute, except that it only applies to searches with the simple paged results control.
If this attribute is not present or is set to zero, then the nsslapd-lookthroughlimit
is used to paged searches as well as non-paged searches.
The corresponding user-level attribute is nsPagedLookThroughLimit
.
Parameter | Description |
---|---|
Entry DN | cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Range | -1 to maximum 32-bit integer in entries (where -1 is unlimited) |
Default Value | 0 |
Syntax | Integer |
Example | nsslapd-pagedlookthroughlimit: 25000 |
4.4.1.16. nsslapd-rangelookthroughlimit
This performance-related attribute specifies the maximum number of entries that the Directory Server will check when examining candidate entries in response to a range search request.
Range searches use operators to set a bracket to search for and return an entire subset of entries within the directory. For example, this searches for every entry modified at or after midnight on January 1:
(modifyTimestamp>=20200101010101Z)
The nature of a range search is that it must evaluate every single entry within the directory to see if it is within the range given. Essentially, a range search is always an all IDs search.
For most users, the look-through limit kicks in and prevents range searches from turning into an all IDs search. This improves overall performance and speeds up range search results. However, some clients or administrative users like Directory Manager may not have a look-through limit set. In that case, a range search can take several minutes to complete or even continue indefinitely.
The nsslapd-rangelookthroughlimit
attribute sets a separate range look-through limit that applies to all users, including Directory Manager.
This allows clients and administrative users to have high look-through limits while still allowing a reasonable limit to be set on potentially performance-impaired range searches.
Unlike other resource limits, this applies to searches by any user, including the Directory Manager, regular users, and other LDAP clients.
Parameter | Description |
---|---|
Entry DN | cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Range | -1 to maximum 32-bit integer in entries (where -1 is unlimited) |
Default Value | 5000 |
Syntax | Integer |
Example | nsslapd-rangelookthroughlimit: 5000 |
4.4.1.17. nsslapd-search-bypass-filter-test
If you enable the nsslapd-search-bypass-filter-test
parameter, Directory Server bypasses filter checks when it builds candidate lists during a search. If you set the parameter to verify
, Directory Server evaluates the filter against the search candidate entries.
Parameter | Description |
---|---|
Entry DN | cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Values | on | off | verify |
Default Value | on |
Syntax | Directory String |
Example | nsslapd-search-bypass-filter-test: on |
4.4.1.18. nsslapd-search-use-vlv-index
The nsslapd-search-use-vlv-index
enables and disables virtual list view (VLV) searches.
Parameter | Description |
---|---|
Entry DN | cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Values | on | off |
Default Value | on |
Syntax | Directory String |
Example | nsslapd-search-use-vlv-index: on |
4.4.1.19. nsslapd-subtree-rename-switch
Every directory entry is stored as a key in an entry index file. The index key maps the current entry DN to its meta entry in the index. This mapping is done either by the RDN of the entry or by the full DN of the entry.
When a subtree entry is allowed to be renamed (meaning, an entry with children entries, effectively renaming the whole subtree), its entries are stored in the entryrdn.db
index, which associates parent and child entries by an assigned ID rather than their DN. If subtree rename operations are not allowed, then the entryrdn.db
index is disabled and the entrydn.db
index is used, which simply uses full DNs, with the implicit parent-child relationships.
Parameter | Description |
---|---|
Entry DN | cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Values | off | on |
Default Value | on |
Syntax | DirectoryString |
Example | nsslapd-subtree-rename-switch: on |
4.4.2. Database Attributes under cn=bdb,cn=config,cn=ldbm database,cn=plugins,cn=config
This section covers global configuration attributes common to all instances are stored in the cn=bdb,cn=config,cn=ldbm database,cn=plugins,cn=config
tree node.
4.4.2.1. nsslapd-cache-autosize
This performance tuning-related attribute sets the percentage of free memory that is used in total for the database and entry cache. For example, if the value is set to 10
, 10% of the system’s free RAM is used for both caches. If this value is set to a value greater than 0
, auto-sizing is enabled for the database and entry cache.
For optimized performance, Red Hat recommends not to disable auto-sizing. However, in certain situations in can be necessary to disable auto-sizing. In this case, set the nsslapd-cache-autosize
attribute to 0
and manually set:
-
the database cache in the
nsslapd-dbcachesize
attribute. -
the entry cache in the
nsslapd-cachememsize
attribute.
For further details about auto-sizing, see the corresponding section in the Red Hat Directory Server Performance Tuning Guide.
If the nsslapd-cache-autosize
and nsslapd-cache-autosize-split
attribute are both set to high values, such as 100
, Directory Server fails to start. To fix the problem, set both parameters to more reasonable values. For example:
nsslapd-cache-autosize: 10 nsslapd-cache-autosize-split: 40
Parameter | Description |
---|---|
Entry DN | cn=bdb,cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Range | 0 to 100. If 0 is set, the default value is used instead. |
Default Value | 10 |
Syntax | Integer |
Example | nsslapd-cache-autosize: 10 |
4.4.2.2. nsslapd-cache-autosize-split
This performance tuning-related attribute sets the percentage of RAM that is used for the database cache. The remaining percentage is used for the entry cache. For example, if the value is set to 40
, the database cache uses 40%, and the entry cache the remaining 60% of the free RAM reserved in the nsslapd-cache-autosize
attribute.
For further details about auto-sizing, see the corresponding section in the Red Hat Directory Server Performance Tuning Guide.
If the nsslapd-cache-autosize
and nsslapd-cache-autosize-split
attribute are both set to high values, such as 100
, Directory Server fails to start. To fix the problem, set both parameters to more reasonable values. For example:
nsslapd-cache-autosize: 10 nsslapd-cache-autosize-split: 40
Parameter | Description |
---|---|
Entry DN | cn=bdb,cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Range | 0 to 99. If 0 is set, the default value is used instead. |
Default Value | 40 |
Syntax | Integer |
Example | nsslapd-cache-autosize-split: 40 |
4.4.2.3. nsslapd-db-checkpoint-interval
This sets the amount of time in seconds after which the Directory Server sends a checkpoint entry to the database transaction log. The database transaction log contains a sequential listing of all recent database operations and is used for database recovery only. A checkpoint entry indicates which database operations have been physically written to the directory database. The checkpoint entries are used to determine where in the database transaction log to begin recovery after a system failure. The nsslapd-db-checkpoint-interval
attribute is absent from dse.ldif
. To change the checkpoint interval, add the attribute to dse.ldif
. This attribute can be dynamically modified using ldapmodify
. For further information on modifying this attribute, see the "Tuning Directory Server Performance" chapter in the Red Hat Directory Server Administration Guide.
This attribute is provided only for system modification/diagnostics and should be changed only with the guidance of Red Hat Technical Support or Red Hat Consulting. Inconsistent settings of this attribute and other configuration attributes may cause the Directory Server to be unstable.
For more information on database transaction logging, see the "Monitoring Server and Database Activity" chapter in the Red Hat Directory Server Administration Guide.
Parameter | Description |
---|---|
Entry DN | cn=bdb,cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Range | 10 to 300 seconds |
Default Value | 60 |
Syntax | Integer |
Example | nsslapd-db-checkpoint-interval: 120 |
4.4.2.4. nsslapd-db-circular-logging
This attribute specifies circular logging for the transaction log files. If this attribute is switched off, old transaction log files are not removed and are kept renamed as old log transaction files. Turning circular logging off can severely degrade server performance and, as such, should only be modified with the guidance of Red Hat Technical Support or Red Hat Consulting.
Parameter | Description |
---|---|
Entry DN | cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Values | on | off |
Default Value | on |
Syntax | DirectoryString |
Example | nsslapd-db-circular-logging: on |
4.4.2.5. nsslapd-db-compactdb-interval
The Berkeley database does not reuse free pages unless the database is explicitly compacted. The compact operation returns the unused pages to the file system and the database file size shrinks. This parameter defines the interval in seconds when the database is compacted. Note that compacting the database is resource-intensive, and thus should not be done to frequently.
This setting does not require a server restart to take effect.
Parameter | Description |
---|---|
Entry DN | cn=bdb,cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Values | 0 (no compaction) to 2147483647 seconds |
Default Value | 2592000 (30 days) |
Syntax | Integer |
Example | nsslapd-compactdb-interval: 2592000 |
4.4.2.6. nsslapd-db-debug
This attribute specifies whether additional error information is to be reported to Directory Server. To report error information, set the parameter to on
. This parameter is meant for troubleshooting; enabling the parameter may slow down the Directory Server.
Parameter | Description |
---|---|
Entry DN | cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Values | on | off |
Default Value | off |
Syntax | DirectoryString |
Example | nsslapd-db-debug: off |
4.4.2.7. nsslapd-db-durable-transactions
This attribute sets whether database transaction log entries are immediately written to the disk. The database transaction log contains a sequential listing of all recent database operations and is used for database recovery only. With durable transactions enabled, every directory change will always be physically recorded in the log file and, therefore, able to be recovered in the event of a system failure. However, the durable transactions feature may also slow the performance of the Directory Server. When durable transactions is disabled, all transactions are logically written to the database transaction log but may not be physically written to disk immediately. If there were a system failure before a directory change was physically written to disk, that change would not be recoverable. The nsslapd-db-durable-transactions
attribute is absent from dse.ldif
. To disable durable transactions, add the attribute to dse.ldif
.
This attribute is provided only for system modification/diagnostics and should be changed only with the guidance of Red Hat Technical Support or Red Hat Consulting. Inconsistent settings of this attribute and other configuration attributes may cause the Directory Server to be unstable.
For more information on database transaction logging, see the "Monitoring Server and Database Activity" chapter in the Red Hat Directory Server Administration Guide.
Parameter | Description |
---|---|
Entry DN | cn=bdb,cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Values | on | off |
Default Value | on |
Syntax | DirectoryString |
Example | nsslapd-db-durable-transactions: on |
4.4.2.8. nsslapd-db-home-directory
To move the database to another physical location for performance reasons, use this parameter to specify the home directory.
This situation will occur only for certain combinations of the database cache size, the size of physical memory, and kernel tuning attributes. In particular, this situation should not occur if the database cache size is less than 100 megabytes.
- The disk is heavily used (more than 1 megabyte per second of data transfer).
- There is a long service time (more than 100ms).
- There is mostly write activity.
If these are all true, use the nsslapd-db-home-directory
attribute to specify a subdirectory of a tempfs
type filesystem.
The directory referenced by the nsslapd-db-home-directory
attribute must be a subdirectory of a filesystem of type tempfs (such as /tmp
). However, Directory Server does not create the subdirectory referenced by this attribute. This directory must be created either manually or by using a script. Failure to create the directory referenced by the nsslapd-db-home-directory
attribute will result in Directory Server being unable to start.
Also, if there are multiple Directory Servers on the same machine, their nsslapd-db-home-directory
attributes must be configured with different directories. Failure to do so will result in the databases for both directories becoming corrupted.
The use of this attribute causes internal Directory Server database files to be moved to the directory referenced by the attribute. It is possible, but unlikely, that the server will no longer start after the files have been moved because not enough memory can be allocated. This is a symptom of an overly large database cache size being configured for the server. If this happens, reduce the size of the database cache size to a value where the server will start again.
Parameter | Description |
---|---|
Entry DN | cn=bdb,cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Values |
Any valid directory name in a tempfs filesystem, such as |
Default Value | |
Syntax | DirectoryString |
Example | nsslapd-db-home-directory: /tmp/slapd-phonebook |
4.4.2.9. nsslapd-db-idl-divisor
This attribute specifies the index block size in terms of the number of blocks per database page. The block size is calculated by dividing the database page size by the value of this attribute. A value of 1
makes the block size exactly equal to the page size. The default value of 0
sets the block size to the page size minus an estimated allowance for internal database overhead. For the majority of installations, the default value should not be changed unless there are specific tuning needs.
Before modifying the value of this attribute, export all databases using the db2ldif
script. Once the modification has been made, reload the databases using the ldif2db
script.
This parameter should only be used by very advanced users.
Parameter | Description |
---|---|
Entry DN | cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Range | 0 to 8 |
Default Value | 0 |
Syntax | Integer |
Example | nsslapd-db-idl-divisor: 2 |
4.4.2.10. nsslapd-db-locks
Lock mechanisms in Directory Server control how many copies of Directory Server processes can run at the same time. The nsslapd-db-locks
parameter sets the maximum number of locks.
Only set this parameter to a higher value if Directory Server runs out of locks and logs libdb: Lock table is out of available locks
error messages. If you set a higher value without a need, this increases the size of the /var/lib/dirsrv/slapd-instance_name/db__db.*
files without any benefit. For more information about monitoring the logs and determining a realistic value, see the corresponding section in the Directory Server Performance Tuning Guide.
The service must be restarted for changes to this attribute to take effect.
Parameter | Description |
---|---|
Entry DN | cn=bdb,cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Range | 0 - 2147483647 |
Default Value | 10000 |
Syntax | Integer |
Example | nsslapd-db-locks: 10000 |
4.4.2.11. nsslapd-db-locks-monitoring-enable
Running out of database locks can lead to data corruption. With the nsslapd-db-locks-monitoring-enable
parameter, you can enable or disable database lock monitoring. If the parameter is enabled, which is the default, Directory Server terminates all searches if the number of active database locks is higher than the percentage threshold configured in nsslapd-db-locks-monitoring-threshold. If an issue occurs, the administrator can increase the number of database locks in the nsslapd-db-locks parameter.
Restart the service for changes to this attribute to take effect.
Parameter | Description |
---|---|
Entry DN | cn=bdb,cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Values | on | off |
Default Value | on |
Syntax | DirectoryString |
Example | nsslapd-db-locks-monitoring-enable: on |
4.4.2.12. nsslapd-db-locks-monitoring-pause
If monitoring of database locks is enabled in the nsslapd-db-locks-monitoring-enable parameter, nsslapd-db-locks-monitoring-pause
defines the interval in milliseconds that the monitoring thread sleeps between the checks.
If you set this parameter to a too high value, the server can run out of database locks before the monitoring check happens. However, setting a too low value can slow down the server.
You do not have to restart the server for this setting to take effect.
Parameter | Description |
---|---|
Entry DN | cn=bdb,cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Values | 0 - 2147483647 (value in milliseconds) |
Default Value | 500 |
Syntax | DirectoryString |
Example | nsslapd-db-locks-monitoring-pause: 500 |
4.4.2.13. nsslapd-db-locks-monitoring-threshold
If monitoring of database locks is enabled in the nsslapd-db-locks-monitoring-enable parameter, nsslapd-db-locks-monitoring-threshold
sets the maximum percentage of used database locks before Directory Server terminates searches to avoid further lock exhaustion.
Restart the service for changes to this attribute to take effect.
Parameter | Description |
---|---|
Entry DN | cn=bdb,cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Values | 70 - 95 |
Default Value | 90 |
Syntax | DirectoryString |
Example | nsslapd-db-locks-monitoring-threshold: 90 |
4.4.2.14. nsslapd-db-logbuf-size
This attribute specifies the log information buffer size. Log information is stored in memory until the buffer fills up or the transaction commit forces the buffer to be written to disk. Larger buffer sizes can significantly increase throughput in the presence of long running transactions, highly concurrent applications, or transactions producing large amounts of data. The log information buffer size is the transaction log size divided by four.
The nsslapd-db-logbuf-size
attribute is only valid if the nsslapd-db-durable-transactions
attribute is set to on
.
Parameter | Description |
---|---|
Entry DN | cn=bdb,cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Range | 32K to maximum 32-bit integer (limited to the amount of memory available on the machine) |
Default Value | 32K |
Syntax | Integer |
Example | nsslapd-db-logbuf-size: 32K |
4.4.2.15. nsslapd-db-logdirectory
This attribute specifies the path to the directory that contains the database transaction log. The database transaction log contains a sequential listing of all recent database operations. Directory Server uses this information to recover the database after an instance shut down unexpectedly.
By default, the database transaction log is stored in the same directory as the directory database. To update this parameter, you must manually update the /etc/dirsrv/slapd-instance_name/dse.ldif
file. For details, see the Changing the Transaction Log Directory section in the Red Hat Directory Server Administration Guide.
Parameter | Description |
---|---|
Entry DN | cn=bdb,cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Values | Any valid path |
Default Value | |
Syntax | DirectoryString |
Example | nsslapd-db-logdirectory: /var/lib/dirsrv/slapd-instance_name/db/ |
4.4.2.16. nsslapd-db-logfile-size
This attribute specifies the maximum size of a single file in the log in bytes. By default, or if the value is set to 0
, a maximum size of 10 megabytes is used. The maximum size is an unsigned 4-byte value.
Parameter | Description |
---|---|
Entry DN | cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Range | 0 to unsigned 4-byte integer |
Default Value | 10MB |
Syntax | Integer |
Example | nsslapd-db-logfile-size: 10 MB |
4.4.2.17. nsslapd-db-page-size
This attribute specifies the size of the pages used to hold items in the database in bytes. The minimum size is 512 bytes, and the maximum size is 64 kilobytes. If the page size is not explicitly set, Directory Server defaults to a page size of 8 kilobytes. Changing this default value can have a significant performance impact. If the page size is too small, it results in extensive page splitting and copying, whereas if the page size is too large it can waste disk space.
Before modifying the value of this attribute, export all databases using the db2ldif
script. Once the modification has been made, reload the databases using the ldif2db
script.
Parameter | Description |
---|---|
Entry DN | cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Range | 512 bytes to 64 kilobytes |
Default Value | 8KB |
Syntax | Integer |
Example | nsslapd-db-page-size: 8KB |
4.4.2.18. nsslapd-db-spin-count
This attribute specifies the number of times that test-and-set mutexes should spin without blocking.
Never touch this value unless you are very familiar with the inner workings of Berkeley DB or are specifically told to do so by Red Hat support.
The default value of 0
causes BDB to calculate the actual value by multiplying the number of available CPU cores (as reported by the nproc
utility or the sysconf(_SC_NPROCESSORS_ONLN)
call) by 50
. For example, with a processor with 8 logical cores, leaving this attribute set to 0
is equivalent to setting it to 400
. It is not possible to turn spinning off entirely - if you want to minimize the amount of times test-and-set mutexes will spin without blocking, set this attribute to 1
.
Parameter | Description |
---|---|
Entry DN | cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Range | 0 to 2147483647 (2^31-1) |
Default Value | 0 |
Syntax | Integer |
Example | nsslapd-db-spin-count: 0 |
4.4.2.19. nsslapd-db-transaction-batch-max-wait
If Section 4.4.2.21, “nsslapd-db-transaction-batch-val” is set, the flushing of transactions is done by a separate thread when the set batch value is reached. However if there are only a few updates, this process might take too long. This parameter controls when transactions should be flushed latest, independently of the batch count. The values is defined in milliseconds.
This parameter is experimental. Never change its value unless you are specifically told to do so by the Red Hat support.
Parameter | Description |
---|---|
Entry DN | cn=bdb,cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Range | 0 - 2147483647 (value in milliseconds) |
Default Value | 50 |
Syntax | Integer |
Example | nsslapd-db-transaction-batch-max-wait: 50 |
4.4.2.20. nsslapd-db-transaction-batch-min-wait
If Section 4.4.2.21, “nsslapd-db-transaction-batch-val” is set, the flushing of transactions is done by a separate thread when the set batch value is reached. However if there are only a few updates, this process might take too long. This parameter controls when transactions should be flushed earliest, independently of the batch count. The values is defined in milliseconds.
This parameter is experimental. Never change its value unless you are specifically told to do so by the Red Hat support.
Parameter | Description |
---|---|
Entry DN | cn=bdb,cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Range | 0 - 2147483647 (value in milliseconds) |
Default Value | 50 |
Syntax | Integer |
Example | nsslapd-db-transaction-batch-min-wait: 50 |
4.4.2.21. nsslapd-db-transaction-batch-val
This attribute specifies how many transactions will be batched before being committed. This attribute can improve update performance when full transaction durability is not required. This attribute can be dynamically modified using ldapmodify
. For further information on modifying this attribute, see the "Tuning Directory Server Performance" chapter in the Red Hat Directory Server Administration Guide.
Setting this value will reduce data consistency and may lead to loss of data. This is because if there is a power outage before the server can flush the batched transactions, those transactions in the batch will be lost.
Do not set this value unless specifically requested to do so by Red Hat support.
If this attribute is not defined or is set to a value of 0
, transaction batching will be turned off, and it will be impossible to make remote modifications to this attribute using LDAP. However, setting this attribute to a value greater than 0
causes the server to delay committing transactions until the number of queued transactions is equal to the attribute value. A value greater than 0
also allows modifications to this attribute remotely using LDAP. A value of 1
for this attribute allows modifications to the attribute setting remotely using LDAP, but results in no batching behavior. A value of 1
at server startup is therefore useful for maintaining normal durability while also allowing transaction batching to be turned on and off remotely when required. Remember that the value for this attribute may require modifying the nsslapd-db-logbuf-size
attribute to ensure sufficient log buffer size for accommodating the batched transactions.
The nsslapd-db-transaction-batch-val
attribute is only valid if the nsslapd-db-durable-transaction
attribute is set to on
.
For more information on database transaction logging, see the "Monitoring Server and Database Activity" chapter in the Red Hat Directory Server Administration Guide.
Parameter | Description |
---|---|
Entry DN | cn=bdb,cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Range | 0 to 30 |
Default Value | 0 (or turned off) |
Syntax | Integer |
Example | nsslapd-db-transaction-batch-val: 5 |
4.4.2.22. nsslapd-db-trickle-percentage
This attribute sets that at least the specified percentage of pages in the shared-memory pool are clean by writing dirty pages to their backing files. This is to ensure that a page is always available for reading in new information without having to wait for a write.
Parameter | Description |
---|---|
Entry DN | cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Range | 0 to 100 |
Default Value | 40 |
Syntax | Integer |
Example | nsslapd-db-trickle-percentage: 40 |
4.4.2.23. nsslapd-db-verbose
This attribute specifies whether to record additional informational and debugging messages when searching the log for checkpoints, doing deadlock detection, and performing recovery. This parameter is meant for troubleshooting, and enabling the parameter may slow down the Directory Server.
Parameter | Description |
---|---|
Entry DN | cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Values | on | off |
Default Value | off |
Syntax | DirectoryString |
Example | nsslapd-db-verbose: off |
4.4.2.24. nsslapd-import-cache-autosize
This performance tuning-related attribute automatically sets the size of the import cache (importCache
) to be used during the command-line-based import process of LDIF files to the database (the ldif2db
operation).
In Directory Server, the import operation can be run as a server task or exclusively on the command-line. In the task mode, the import operation runs as a general Directory Server operation. The nsslapd-import-cache-autosize
attribute enables the import cache to be set automatically to a predetermined size when the import operation is run on the command-line. The attribute can also be used by Directory Server during the task mode import for allocating a specified percentage of free memory for import cache.
By default, the nsslapd-import-cache-autosize
attribute is enabled and is set to a value of -1
. This value autosizes the import cache for the ldif2db
operation only, automatically allocating fifty percent (50%) of the free physical memory for the import cache. The percentage value (50%) is hard-coded and cannot be changed.
Setting the attribute value to 50
(nsslapd-import-cache-autosize: 50
) has the same effect on performance during an ldif2db
operation. However, such a setting will have the same effect on performance when the import operation is run as a Directory Server task. The -1
value autosizes the import cache just for the ldif2db
operation and not for any, including import, general Directory Server tasks.
The purpose of a -1
setting is to enable the ldif2db
operation to benefit from free physical memory but, at the same time, not compete for valuable memory with the entry cache, which is used for general operations of the Directory Server.
Setting the nsslapd-import-cache-autosize
attribute value to 0
turns off the import cache autosizing feature - that is, no autosizing occurs during either mode of the import operation. Instead, Directory Server uses the nsslapd-import-cachesize
attribute for import cache size, with a default value of 20000000
.
There are three caches in the context of Directory Server: database cache, entry cache, and import cache. The import cache is only used during the import operation. The nsslapd-cache-autosize
attribute, which is used for autosizing the entry cache and database cache, is used during the Directory Server operations only and not during the ldif2db
command-line operation; the attribute value is the percentage of free physical memory to be allocated for the entry cache and database cache.
If both the autosizing attributes, nsslapd-cache-autosize
and nsslapd-import-cache-autosize
, are enabled, ensure that their sum is less than 100.
Parameter | Description |
---|---|
Entry DN | cn=bdb,cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Range | -1, 0 (turns import cache autosizing off) to 100 |
Default Value | -1 (turns import cache autosizing on for ldif2db only and allocates 50% of the free physical memory to import cache) |
Syntax | Integer |
Example | nsslapd-import-cache-autosize: -1 |
4.4.2.25. nsslapd-dbcachesize
This performance tuning-related attribute specifies the database index cache size, in bytes. This is one of the most important values for controlling how much physical RAM the directory server uses.
This is not the entry cache. This is the amount of memory the Berkeley database back end will use to cache the indexes (the .db
files) and other files. This value is passed to the Berkeley DB API function set_cachesize
. If automatic cache resizing is activated, this attribute is overridden when the server replaces these values with its own guessed values at a later stage of the server startup.
For more technical information on this attribute, see the cache size section of the Berkeley DB reference guide at https://docs.oracle.com/cd/E17076_04/html/programmer_reference/general_am_conf.html#am_conf_cachesize.
Attempting to set a value that is not a number or is too big for a 32-bit signed integer returns an LDAP_UNWILLING_TO_PERFORM
error message with additional error information explaining the problem.
Do not set the database cache size manually. Red Hat recommends to use the database cache auto-sizing feature for optimized performance. For further see the corresponding section in the Red Hat Directory Server Performance Tuning Guide.
The server has to be restarted for changes to this attribute to go into effect.
Parameter | Description |
---|---|
Entry DN | cn=bdb,cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Range | 500 kilobytes to 4 gigabytes for 32-bit platforms and 500 kilobytes to 2^64-1 for 64-bit platforms |
Default Value | |
Syntax | Integer |
Example | nsslapd-dbcachesize: 10000000 |
4.4.2.26. nsslapd-dbncache
This attribute can split the LDBM cache into equally sized separate pieces of memory. It is possible to specify caches that are large enough so that they cannot be allocated contiguously on some architectures; for example, some systems limit the amount of memory that may be allocated contiguously by a process. If nsslapd-dbncache
is 0
or 1
, the cache will be allocated contiguously in memory. If it is greater than 1
, the cache will be broken up into ncache
, equally sized separate pieces of memory.
To configure a dbcache size larger than 4 gigabytes, add the nsslapd-dbncache
attribute to cn=config,cn=ldbm database,cn=plugins,cn=config
between the nsslapd-dbcachesize
and nsslapd-db-logdirectory
attribute lines.
Set this value to an integer that is one-quarter (1/4) the amount of memory in gigabytes. For example, for a 12 gigabyte system, set the nsslapd-dbncache
value to 3
; for an 8 gigabyte system, set it to 2
.
This attribute is provided only for system modification/diagnostics and should be changed only with the guidance of Red Hat technical support or Red Hat professional services. Inconsistent settings of this attribute and other configuration attributes may cause the Directory Server to be unstable.
The server has to be restarted for changes to this attribute to go into effect.
Parameter | Description |
---|---|
Entry DN | cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Values | 1 to 4 |
Default Value | 1 |
Syntax | Integer |
Example | nsslapd-dbncache: 1 |
4.4.2.27. nsslapd-search-bypass-filter-test
If you enable the nsslapd-search-bypass-filter-test
parameter, Directory Server bypasses filter checks when it builds candidate lists during a search. If you set the parameter to verify
, Directory Server evaluates the filter against the search candidate entries.
Parameter | Description |
---|---|
Entry DN | cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Values | on | off | verify |
Default Value | on |
Syntax | Directory String |
Example | nsslapd-search-bypass-filter-test: on |
4.4.3. Database Attributes under cn=monitor,cn=ldbm database,cn=plugins,cn=config
Global read-only attributes containing database statistics for monitoring activity on the databases are stored in the cn=monitor,cn=ldbm database,cn=plugins,cn=config
tree node. For more information on these entries, see the "Monitoring Server and Database Activity" chapter in the Red Hat Directory Server Administration Guide.
dbcachehits
This attribute shows the requested pages found in the database.
dbcachetries
This attribute shows the total cache lookups.
dbcachehitratio
This attribute shows the percentage of requested pages found in the database cache (hits/tries).
dbcachepagein
This attribute shows the pages read into the database cache.
dbcachepageout
This attribute shows the pages written from the database cache to the backing file.
dbcacheroevict
This attribute shows the clean pages forced from the cache.
dbcacherwevict
This attribute shows the dirty pages forced from the cache.
normalizedDNcachetries
Total number of cache lookups since the instance was started.
normalizedDNcachehits
Normalized DNs found within the cache.
normalizedDNcachemisses
Normalized DNs not found within the cache.
normalizedDNcachehitratio
Percentage of the normalized DNs found in the cache.
currentNormalizedDNcachesize
Current size of the normalized DN cache in bytes.
maxNormalizedDNcachesize
Current value of the nsslapd-ndn-cache-max-size
parameter. For details how to update this setting, see Section 3.1.1.128, “nsslapd-ndn-cache-max-size”.
currentNormalizedDNcachecount
Number of normalized cached DNs.
4.4.4. Database Attributes under cn=database_name,cn=ldbm database,cn=plugins,cn=config
The cn=database_name
subtree contains all the configuration data for the user-defined database.
The cn=userRoot
subtree is called userRoot by default. However, this is not hard-coded and, given the fact that there are going to be multiple database instances, this name is changed and defined by the user as and when new databases are added. The cn=userRoot
database referenced can be any user database.
The following attributes are common to databases, such as cn=userRoot
.
4.4.4.1. nsslapd-cachesize
This attribute has been deprecated. To resize the entry cache, use nsslapd-cachememsize.
This performance tuning-related attribute specifies the cache size in terms of the number of entries it can hold. However, this attribute is deprecated in favor of the nsslapd-cachememsize
attribute, which sets an absolute allocation of RAM for the entry cache size, as described in Section 4.4.4.2, “nsslapd-cachememsize”.
Attempting to set a value that is not a number or is too big for a 32-bit signed integer (on 32-bit systems) returns an LDAP_UNWILLING_TO_PERFORM
error message with additional error information explaining the problem.
The server has to be restarted for changes to this attribute to go into effect.
The performance counter for this setting goes to the highest 64-bit integer, even on 32-bit systems, but the setting itself is limited on 32-bit systems to the highest 32-bit integer because of how the system addresses memory.
Parameter | Description |
---|---|
Entry DN | cn=database_name,cn=ldbm database,cn=plugins,cn=config |
Valid Range | 1 to 232-1 on 32-bit systems or 263-1 on 64-bit systems or -1, which means limitless |
Default Value | -1 |
Syntax | Integer |
Example | nsslapd-cachesize: -1 |
4.4.4.2. nsslapd-cachememsize
This performance tuning-related attribute specifies the size, in bytes, for the available memory space for the entry cache. The simplest method is limiting cache size in terms of memory occupied. Activating automatic cache resizing overrides this attribute, replacing these values with its own guessed values at a later stage of the server startup.
Attempting to set a value that is not a number or is too big for a 32-bit signed integer (on 32-bit systems) returns an LDAP_UNWILLING_TO_PERFORM
error message with additional error information explaining the problem.
The performance counter for this setting goes to the highest 64-bit integer, even on 32-bit systems, but the setting itself is limited on 32-bit systems to the highest 32-bit integer because of how the system addresses memory.
Do not set the database cache size manually. Red Hat recommends to use the entry cache auto-sizing feature for optimized performance. For further see the corresponding section in the Red Hat Directory Server Performance Tuning Guide.
Parameter | Description |
---|---|
Entry DN | cn=database_name,cn=ldbm database,cn=plugins,cn=config |
Valid Range | 500 kilobytes to 264-1 on 64-bit systems |
Default Value | 209715200 (200 MiB) |
Syntax | Integer |
Example | nsslapd-cachememsize: 209715200 |
4.4.4.3. nsslapd-directory
This attribute specifies the path to the database instance. If it is a relative path, it starts from the path specified by nsslapd-directory
in the global database entry cn=config,cn=ldbm database,cn=plugins,cn=config
. The database instance directory is named after the instance name and located in the global database directory, by default. After the database instance has been created, do not modify this path, because any changes risk preventing the server from accessing data.
Parameter | Description |
---|---|
Entry DN | cn=database_name,cn=ldbm database,cn=plugins,cn=config |
Valid Values | Any valid path to the database instance |
Default Value | |
Syntax | DirectoryString |
Example | nsslapd-directory: /var/lib/dirsrv/slapd-instance/db/userRoot |
4.4.4.4. nsslapd-dncachememsize
This performance tuning-related attribute specifies the size, in bytes, for the available memory space for the DN cache. The DN cache is similar to the entry cache for a database, only its table stores only the entry ID and the entry DN. This allows faster lookups for rename and moddn operations.
The simplest method is limiting cache size in terms of memory occupied.
Attempting to set a value that is not a number or is too big for a 32-bit signed integer (on 32-bit systems) returns an LDAP_UNWILLING_TO_PERFORM
error message with additional error information explaining the problem.
The performance counter for this setting goes to the highest 64-bit integer, even on 32-bit systems, but the setting itself is limited on 32-bit systems to the highest 32-bit integer because of how the system addresses memory.
Parameter | Description |
---|---|
Entry DN | cn=database_name,cn=ldbm database,cn=plugins,cn=config |
Valid Range | 500 kilobytes to 232-1 on 32-bit systems and to 264-1 on 64-bit systems |
Default Value | 10,485,760 (10 megabytes) |
Syntax | Integer |
Example | nsslapd-dncachememsize: 10485760 |
4.4.4.5. nsslapd-readonly
This attribute specifies read-only mode for a single back-end instance. If this attribute has a value of off
, then users have all read, write, and execute permissions allowed by their access permissions.
Parameter | Description |
---|---|
Entry DN | cn=database_name,cn=ldbm database,cn=plugins,cn=config |
Valid Values | on | off |
Default Value | off |
Syntax | DirectoryString |
Example | nsslapd-readonly: off |
4.4.4.6. nsslapd-require-index
When switched to on
, this attribute allows one to refuse unindexed searches. This performance-related attribute avoids saturating the server with erroneous searches.
Parameter | Description |
---|---|
Entry DN | cn=database_name,cn=ldbm database,cn=plugins,cn=config |
Valid Values | on | off |
Default Value | off |
Syntax | DirectoryString |
Example | nsslapd-require-index: off |
4.4.4.7. nsslapd-require-internalop-index
When a plug-in modifies data, it has a write lock on the database. On large databases, if a plug-in then executes an unindexed search, the plug-in can use all database locks and corrupt the database or the server becomes unresponsive. To avoid this problem, you can reject internal unindexed searches by enabling the nsslapd-require-internalop-index
parameter.
Parameter | Description |
---|---|
Entry DN | cn=database_name,cn=ldbm database,cn=plugins,cn=config |
Valid Values | on | off |
Default Value | off |
Syntax | DirectoryString |
Example | nsslapd-require-internalop-index: off |
4.4.4.8. nsslapd-suffix
This attribute specifies the suffix of the database link. This is a single-valued attribute because each database instance can have only one suffix. Previously, it was possible to have more than one suffix on a single database instance, but this is no longer the case. As a result, this attribute is single-valued to enforce the fact that each database instance can only have one suffix entry. Any changes made to this attribute after the entry has been created take effect only after the server containing the database link is restarted.
Parameter | Description |
---|---|
Entry DN | cn=database_name,cn=ldbm database,cn=plugins,cn=config |
Valid Values | Any valid DN |
Default Value | |
Syntax | DirectoryString |
Example | nsslapd-suffix: o=Example |
4.4.4.9. vlvBase
This attribute sets the base DN for which the browsing or virtual list view (VLV) index is created.
For more information on VLV indexes, see the indexing chapter in the Administration Guide.
Parameter | Description |
---|---|
Entry DN | cn=index_name,cn=userRoot,cn=ldbm database,cn=plugins,cn=config |
Valid Values | Any valid DN |
Default Value | |
Syntax | DirectoryString |
Example | vlvBase: ou=People,dc=example,dc=com |
4.4.4.10. vlvEnabled
The vlvEnabled
attribute provides status information about a specific VLV index, and Directory Server sets this attribute at run time. Although vlvEnabled
is shown in the configuration, you cannot modify this attribute.
For more information on VLV indexes, see the indexing chapter in the Administration Guide.
Parameter | Description |
---|---|
Entry DN | cn=index_name,cn=userRoot,cn=ldbm database,cn=plugins,cn=config |
Valid Values | 0 (disabled) | 1 (enabled) |
Default Value | 1 |
Syntax | DirectoryString |
Example | vlvEnbled: 0 |
4.4.4.11. vlvFilter
The browsing or virtual list view (VLV) index is created by running a search according to a filter and including entries which match that filter in the index. The filter is specified in the vlvFilter
attribute.
For more information on VLV indexes, see the indexing chapter in the Administration Guide.
Parameter | Description |
---|---|
Entry DN | cn=index_name,cn=userRoot,cn=ldbm database,cn=plugins,cn=config |
Valid Values | Any valid LDAP filter |
Default Value | |
Syntax | DirectoryString |
Example | vlvFilter: ( |
4.4.4.12. vlvIndex (Object Class)
A browsing index or virtual list view (VLV) index dynamically generates an abbreviated index of entry headers that makes it much faster to visually browse large indexes. A VLV index definition has two parts: one which defines the index and one which defines the search used to identify entries to add to the index. The vlvIndex
object class defines the index entry.
This object class is defined in Directory Server.
Superior Class
top
OID
2.16.840.1.113730.3.2.42
Table 4.2. Required Attributes
Attribute | Definition |
---|---|
objectClass | Defines the object classes for the entry. |
cn | Gives the common name of the entry. |
Identifies the attribute list that the browsing index (virtual list view index) is sorted on. |
Table 4.3. Allowed Attributes
Attribute | Definition |
---|---|
Stores the availability of the browsing index. | |
Contains the count the browsing index is used. |
4.4.4.13. vlvScope
This attribute sets the scope of the search to run for entries in the browsing or virtual list view (VLV) index.
For more information on VLV indexes, see the indexing chapter in the Administration Guide.
Parameter | Description |
---|---|
Entry DN | cn=index_name,cn=userRoot,cn=ldbm database,cn=plugins,cn=config |
Valid Values | * 1 (one-level or children search) * 2 (subtree search) |
Default Value | |
Syntax | Integer |
Example | vlvScope: 2 |
4.4.4.14. vlvSearch (Object Class)
A browsing index or virtual list view (VLV) index dynamically generates an abbreviated index of entry headers that makes it much faster to visually browse large indexes. A VLV index definition has two parts: one which defines the index and one which defines the search used to identify entries to add to the index. The vlvSearch
object class defines the search filter entry.
This object class is defined in Directory Server.
Superior Class
top
OID
2.16.840.1.113730.3.2.38
Table 4.4. Required Attributes
Attribute | Definition |
---|---|
objectClass | Defines the object classes for the entry. |
Identifies base DN the browsing index is created. | |
Identifies the scope to define the browsing index. | |
Identifies the filter string to define the browsing index. |
Table 4.5. Allowed Attributes
Attribute | Definition |
---|---|
multiLineDescription | Gives a text description of the entry. |
4.4.4.15. vlvSort
This attribute sets the sort order for returned entries in the browsing or virtual list view (VLV) index.
The entry for this attribute is a vlvIndex
entry beneath the vlvSearch
entry.
For more information on VLV indexes, see the indexing chapter in the Administration Guide.
Parameter | Description |
---|---|
Entry DN | cn=index_name,cn=index_name,cn=userRoot,cn=ldbm database,cn=plugins,cn=config |
Valid Values | Any Directory Server attributes, in a space-separated list |
Default Value | |
Syntax | DirectoryString |
Example | vlvSort: cn givenName o ou sn |
4.4.4.16. vlvUses
The vlvUses
attribute contains the count the browsing index uses, and Directory Server sets this attribute at run time. Although vlvUses
is shown in the configuration, you cannot modify this attribute.
For more information on VLV indexes, see the indexing chapter in the Administration Guide.
Parameter | Description |
---|---|
Entry DN | cn=index_name,cn=userRoot,cn=ldbm database,cn=plugins,cn=config |
Valid Values | N/A |
Default Value | |
Syntax | DirectoryString |
Example | vlvUses: 800 |
4.4.5. Database Attributes under cn=database,cn=monitor,cn=ldbm database,cn=plugins,cn=config
The attributes in this tree node entry are all read-only, database performance counters. All of the values for these attributes are 32-bit integers, except for entrycachehits
and entrycachetries
.
If the nsslapd-counters
attribute in cn=config
is set to on
, then some of the counters kept by the Directory Server instance increment using 64-bit integers, even on 32-bit machines or with a 32-bit version of Directory Server. For the database monitoring, the entrycachehits
and entrycachetries
counters use 64-bit integers.
The nsslapd-counters
attribute enables 64-bit support for these specific database and server counters. The counters which use 64-bit integers are not configurable; the 64-bit integers are either enabled for all the allowed counters or disabled for all allowed counters.
nsslapd-db-abort-rate
This attribute shows the number of transactions that have been aborted.
nsslapd-db-active-txns
This attribute shows the number of transactions that are currently active.
nsslapd-db-cache-hit
This attribute shows the requested pages found in the cache.
nsslapd-db-cache-try
This attribute shows the total cache lookups.
nsslapd-db-cache-region-wait-rate
This attribute shows the number of times that a thread of control was forced to wait before obtaining the region lock.
nsslapd-db-cache-size-bytes
This attribute shows the total cache size in bytes.
nsslapd-db-clean-pages
This attribute shows the clean pages currently in the cache.
nsslapd-db-commit-rate
This attribute shows the number of transactions that have been committed.
nsslapd-db-deadlock-rate
This attribute shows the number of deadlocks detected.
nsslapd-db-dirty-pages
This attribute shows the dirty pages currently in the cache.
nsslapd-db-hash-buckets
This attribute shows the number of hash buckets in buffer hash table.
nsslapd-db-hash-elements-examine-rate
This attribute shows the total number of hash elements traversed during hash table lookups.
nsslapd-db-hash-search-rate
This attribute shows the total number of buffer hash table lookups.
nsslapd-db-lock-conflicts
This attribute shows the total number of locks not immediately available due to conflicts.
nsslapd-db-lock-region-wait-rate
This attribute shows the number of times that a thread of control was forced to wait before obtaining the region lock.
nsslapd-db-lock-request-rate
This attribute shows the total number of locks requested.
nsslapd-db-lockers
This attribute shows the number of current lockers.
nsslapd-db-log-bytes-since-checkpoint
This attribute shows the number of bytes written to this log since the last checkpoint.
nsslapd-db-log-region-wait-rate
This attribute shows the number of times that a thread of control was forced to wait before obtaining the region lock.
nsslapd-db-log-write-rate
This attribute shows the number of megabytes and bytes written to this log.
nsslapd-db-longest-chain-length
This attribute shows the longest chain ever encountered in buffer hash table lookups.
nsslapd-db-page-create-rate
This attribute shows the pages created in the cache.
nsslapd-db-page-read-rate
This attribute shows the pages read into the cache.
nsslapd-db-page-ro-evict-rate
This attribute shows the clean pages forced from the cache.
nsslapd-db-page-rw-evict-rate
This attribute shows the dirty pages forced from the cache.
nsslapd-db-page-trickle-rate
This attribute shows the dirty pages written using the memp_trickle
interface.
nsslapd-db-page-write-rate
This attribute shows the pages read into the cache.
nsslapd-db-pages-in-use
This attribute shows all pages, clean or dirty, currently in use.
nsslapd-db-txn-region-wait-rate
This attribute shows the number of times that a thread of control was force to wait before obtaining the region lock.
currentdncachecount
This attribute shows the number of DNs currently present in the DN cache.
currentdncachesize
This attribute shows the total size, in bytes, of DNs currently present in the DN cache.
maxdncachesize
This attribute shows the maximum size, in bytes, of DNs that can be maintained in the database DN cache.
4.4.6. Database Attributes under cn=monitor,cn=userRoot,cn=ldbm database,cn=plugins,cn=config
The attributes in this tree node entry are all read-only, database performance counters.
If the nsslapd-counters
attribute in cn=config
is set to on
, then some of the counters kept by the Directory Server instance increment using 64-bit integers, even on 32-bit machines or with a 32-bit version of Directory Server. For database monitoring, the entrycachehits
and entrycachetries
counters use 64-bit integers.
The nsslapd-counters
attribute enables 64-bit support for these specific database and server counters. The counters which use 64-bit integers are not configurable; the 64-bit integers are either enabled for all the allowed counters or disabled for all allowed counters.
dbfilename-number
This attribute gives the name of the file and provides a sequential integer identifier (starting at 0) for the file. All associated statistics for the file are given this same numerical identifier.
dbfilecachehit-number
This attribute gives the number of times that a search requiring data from this file was performed and that the data were successfully obtained from the cache. The number in this attributes name corresponds to the one in dbfilename
.
dbfilecachemiss-number
This attribute gives the number of times that a search requiring data from this file was performed and that the data could not be obtained from the cache. The number in this attributes name corresponds to the one in dbfilename
.
dbfilepagein-number
This attribute gives the number of pages brought to the cache from this file. The number in this attributes name corresponds to the one in dbfilename
.
dbfilepageout-number
This attribute gives the number of pages for this file written from cache to disk. The number in this attributes name corresponds to the one in dbfilename
.
currentDNcachecount
Number of cached DNs.
currentDNcachesize
Current size of the DN cache in bytes.
DNcachehitratio
Percentage of the DNs found in the cache.
DNcachehits
DNs found within the cache.
DNcachemisses
DNs not found within the cache.
DNcachetries
Total number of cache lookups since the instance was started.
maxDNcachesize
Current value of the nsslapd-ndn-cache-max-size
parameter. For details how to update this setting, see Section 3.1.1.128, “nsslapd-ndn-cache-max-size”.
4.4.7. Database Attributes under cn=default indexes,cn=config,cn=ldbm database,cn=plugins,cn=config
The set of default indexes is stored here. Default indexes are configured per back end in order to optimize Directory Server functionality for the majority of setup scenarios. All indexes, except system-essential ones, can be removed, but care should be taken so as not to cause unnecessary disruptions. For further information on indexes, see the "Managing Indexes" chapter in the Red Hat Directory Server Administration Guide.
4.4.7.1. cn
This attribute provides the name of the attribute to index.
Parameter | Description |
---|---|
Entry DN | cn=default indexes,cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Values | Any valid index cn |
Default Value | None |
Syntax | DirectoryString |
Example | cn: aci |
4.4.7.2. nsIndex
This object class defines an index in the back end database. This object is defined in Directory Server.
Superior Class
top
OID
2.16.840.1.113730.3.2.44
Table 4.6. Required Attributes
Attribute | Definition |
---|---|
objectClass | Defines the object classes for the entry. |
cn | Gives the common name of the entry. |
Identify whether or not the index is a system defined index. |
Table 4.7. Allowed Attributes
Attribute | Definition |
---|---|
description | Gives a text description of the entry. |
Identifies the index type. | |
Identifies the matching rule. |
4.4.7.3. nsIndexType
This optional, multi-valued attribute specifies the type of index for Directory Server operations and takes the values of the attributes to be indexed. Each required index type has to be entered on a separate line.
Parameter | Description |
---|---|
Entry DN | cn=default indexes,cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Values | * pres = presence index * eq = equality index * approx = approximate index * sub = substring index * matching rule = international index * index browse = browsing index |
Default Value | |
Syntax | DirectoryString |
Example | nsIndexType: eq |
4.4.7.4. nsMatchingRule
This optional, multi-valued attribute specifies the ordering matching rule name or OID used to match values and to generate index keys for the attribute. This is most commonly used to ensure that equality and range searches work correctly for languages other than English (7-bit ASCII).
This is also used to allow range searches to work correctly for integer syntax attributes that do not specify an ordering matching rule in their schema definition. uidNumber
and gidNumber
are two commonly used attributes that fall into this category.
For example, for a uidNumber
that uses integer syntax, the rule attribute could be nsMatchingRule: integerOrderingMatch
.
Any change to this attribute will not take effect until the change is saved and the index is rebuilt using db2index
, which is described in more detail in the "Managing Indexes" chapter of the Red Hat Directory Server Administration Guide).
Parameter | Description |
---|---|
Entry DN | cn=default indexes,cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Values | Any valid collation order object identifier (OID) |
Default Value | None |
Syntax | DirectoryString |
Example | nsMatchingRule: 2.16.840.1.113730.3.3.2.3.1 (For Bulgarian) |
4.4.7.5. nsSystemIndex
This mandatory attribute specifies whether the index is a system index, an index which is vital for Directory Server operations. If this attribute has a value of true
, then it is system-essential. System indexes should not be removed, as this will seriously disrupt server functionality.
Parameter | Description |
---|---|
Entry DN | cn=default indexes,cn=config,cn=ldbm database,cn=plugins,cn=config |
Valid Values | true | false |
Default Value | |
Syntax | DirectoryString |
Example | nssystemindex: true |
4.4.8. Database Attributes under cn=index,cn=database_name,cn=ldbm database,cn=plugins,cn=config
In addition to the set of default indexes that are stored under cn=default indexes,cn=config,cn=ldbm database,cn=plugins,cn=config
, custom indexes can be created for user-defined back end instances; these are stored under cn=index,cn=database_name,cn=ldbm database,cn=plugins,cn=config
. Each indexed attribute represents a subentry under the cn=config
information tree nodes, as shown in the following diagram:
Figure 4.2. Indexed Attribute Representing a Subentry

For example, the index file for the aci
attribute under o=UserRoot
appears in the Directory Server as follows:
dn:cn=aci,cn=index,cn=UserRoot,cn=ldbm database,cn=plugins,cn=config objectclass:top objectclass:nsIndex cn:aci nsSystemIndex:true nsIndexType:pres
These entries share all of the indexing attributes listed for the default indexes in Section 4.4.7, “Database Attributes under cn=default indexes,cn=config,cn=ldbm database,cn=plugins,cn=config”. For further information about indexes, see the "Managing Indexes" chapter in the Red Hat Directory Server Administration Guide.
4.4.8.1. nsIndexIDListScanLimit
This multi-valued parameter defines a search limit for certain indices or to use no ID list. For further information, see the corresponding section in the Directory Server Performance Tuning Guide.
Parameter | Description |
---|---|
Entry DN | cn=attribute_name,cn=index,cn=database_name,cn=ldbm database,cn=plugins,cn=config |
Valid Values | See the corresponding section in the Directory Server Performance Tuning Guide. |
Default Value | |
Syntax | DirectoryString |
Example | nsIndexIDListScanLimit: limit=0 type=eq values=inetorgperson |
4.4.8.2. nsSubStrBegin
By default, for a search to be indexed, the search string must be at least three characters long, without counting any wildcard characters. For example, the string abc
would be an indexed search while ab*
would not be. Indexed searches are significantly faster than unindexed searches, so changing the minimum length of the search key is helpful to increase the number of indexed searches.
This substring length can be edited based on the position of any wildcard characters. The nsSubStrBegin
attribute sets the required number of characters for an indexed search for the beginning of a search string, before the wildcard. For example:
abc*
If the value of this attribute is changed, then the index must be regenerated using db2index
.
Parameter | Description |
---|---|
Entry DN | cn=attribute_name,cn=index,cn=database_name,cn=ldbm database,cn=plugins,cn=config |
Valid Values | Any integer |
Default Value | 3 |
Syntax | Integer |
Example | nsSubStrBegin: 2 |
4.4.8.3. nsSubStrEnd
By default, for a search to be indexed, the search string must be at least three characters long, without counting any wildcard characters. For example, the string abc
would be an indexed search while ab*
would not be. Indexed searches are significantly faster than unindexed searches, so changing the minimum length of the search key is helpful to increase the number of indexed searches.
This substring length can be edited based on the position of any wildcard characters. The nsSubStrEnd
attribute sets the required number of characters for an indexed search for the end of a search string, after the wildcard. For example:
*xyz
If the value of this attribute is changed, then the index must be regenerated using db2index
.
Parameter | Description |
---|---|
Entry DN | cn=attribute_name,cn=index,cn=database_name,cn=ldbm database,cn=plugins,cn=config |
Valid Values | Any integer |
Default Value | 3 |
Syntax | Integer |
Example | nsSubStrEnd: 2 |
4.4.8.4. nsSubStrMiddle
By default, for a search to be indexed, the search string must be at least three characters long, without counting any wildcard characters. For example, the string abc
would be an indexed search while ab*
would not be. Indexed searches are significantly faster than unindexed searches, so changing the minimum length of the search key is helpful to increase the number of indexed searches.
This substring length can be edited based on the position of any wildcard characters. The nsSubStrMiddle
attribute sets the required number of characters for an indexed search where a wildcard is used in the middle of a search string. For example:
ab*z
If the value of this attribute is changed, then the index must be regenerated using db2index
.
Parameter | Description |
---|---|
Entry DN | cn=attribute_name,cn=index,cn=database_name,cn=ldbm database,cn=plugins,cn=config |
Valid Values | Any integer |
Default Value | 3 |
Syntax | Integer |
Example | nsSubStrMiddle: 3 |
4.4.9. Database Attributes under cn=attributeName,cn=encrypted attributes,cn=database_name,cn=ldbm database,cn=plugins,cn=config
The nsAttributeEncryption
object class allows selective encryption of attributes within a database. Extremely sensitive information such as credit card numbers and government identification numbers may not be protected enough by routine access control measures. Normally, these attribute values are stored in CLEAR within the database; encrypting them while they are stored adds another layer of protection. This object class has one attribute, nsEncryptionAlgorithm
, which sets the encryption cipher used per attribute. Each encrypted attribute represents a subentry under the above cn=config
information tree nodes, as shown in the following diagram:
Figure 4.3. Encrypted Attributes under the cn=config Node

For example, the database encryption file for the userPassword
attribute under o=UserRoot
appears in the Directory Server as follows:
dn:cn=userPassword,cn=encrypted attributes,o=UserRoot,cn=ldbm database, cn=plugins,cn=config objectclass:top objectclass:nsAttributeEncryption cn:userPassword nsEncryptionAlgorithm:AES
To configure database encryption, see the "Database Encryption" section of the "Configuring Directory Databases" chapter in the Red Hat Directory Server Administration Guide. For more information about indexes, see the "Managing Indexes" chapter in the Red Hat Directory Server Administration Guide.
4.4.9.1. nsAttributeEncryption (Object Class)
This object class is used for core configuration entries which identify and encrypt selected attributes within a Directory Server database.
This object class is defined in Directory Server.
Superior Class
top
OID
2.16.840.1.113730.3.2.316
Table 4.8. Required Attributes
objectClass | Defines the object classes for the entry. |
cn | Specifies the attribute being encrypted using its common name. |
The encryption cipher used. |
4.4.9.2. nsEncryptionAlgorithm
nsEncryptionAlgorithm
selects the cipher used by nsAttributeEncryption
. The algorithm can be set per encrypted attribute.
Parameter | Description |
---|---|
Entry DN | cn=attributeName,cn=encrypted attributes,cn=database_name,cn=ldbm database,cn=plugins,cn=config |
Valid Values | The following are supported ciphers: * Advanced Encryption Standard Block Cipher (AES) * Triple Data Encryption Standard Block Cipher (3DES) |
Default Value | |
Syntax | DirectoryString |
Example | nsEncryptionAlgorithm: AES |
4.5. Database Link Plug-in Attributes (Chaining Attributes)
The database link plug-in attributes are also organized in an information tree, as shown in the following diagram:
Figure 4.4. Database Link Plug-in

All plug-in technology used by the database link instances is stored in the cn=chaining database
plug-in node. This section presents the additional attribute information for the three nodes marked in bold in the cn=chaining database,cn=plugins,cn=config
information tree in Figure 4.4, “Database Link Plug-in”.
4.5.1. Database Link Attributes under cn=config,cn=chaining database,cn=plugins,cn=config
This section covers global configuration attributes common to all instances are stored in the cn=config,cn=chaining database,cn=plugins,cn=config
tree node.
4.5.1.1. nsActiveChainingComponents
This attribute lists the components using chaining. A component is any functional unit in the server. The value of this attribute overrides the value in the global configuration attribute. To disable chaining on a particular database instance, use the value None
. This attribute also allows the components used to chain to be altered. By default, no components are allowed to chain, which explains why this attribute will probably not appear in a list of cn=config,cn=chaining database,cn=config
attributes, as LDAP considers empty attributes to be non-existent.
Parameter | Description |
---|---|
Entry DN | cn=config,cn=chaining database,cn=plugins,cn=config |
Valid Values | Any valid component entry |
Default Value | None |
Syntax | DirectoryString |
Example | nsActiveChainingComponents: cn=uid uniqueness,cn=plugins,cn=config |
4.5.1.2. nsMaxResponseDelay
This error detection, performance-related attribute specifies the maximum amount of time it can take a remote server to respond to an LDAP operation request made by a database link before an error is suspected. Once this delay period has been met, the database link tests the connection with the remote server.
Parameter | Description |
---|---|
Entry DN | cn=config,cn=chaining database,cn=plugins,cn=config |
Valid Values | Any valid delay period in seconds |
Default Value | 60 seconds |
Syntax | Integer |
Example | nsMaxResponseDelay: 60 |
4.5.1.3. nsMaxTestResponseDelay
This error detection, performance-related attribute specifies the duration of the test issued by the database link to check whether the remote server is responding. If a response from the remote server is not returned before this period has passed, the database link assumes the remote server is down, and the connection is not used for subsequent operations.
Parameter | Description |
---|---|
Entry DN | cn=config,cn=chaining database,cn=plugins,cn=config |
Valid Values | Any valid delay period in seconds |