6.4. Adjusting the DN cache size
Red Hat recommends using the built-in cache auto-sizing feature for optimized performance. Only change this value if you need to purposely deviate from the auto-tuned values.
The nsslapd-dncachememsize attribute specifies the size, in bytes, for the available memory space for the Distinguished Names (DN) cache. The DN cache is similar to the entry cache for a database, but its table stores only the entry ID and the entry DN, which allows faster lookups for rename and moddn operations.
| Default value |
|
| Valid range |
|
| Entry DN location |
|
Conditions préalables
- Le mot de passe du gestionnaire de répertoire LDAP
Procédure
(Optional) Display the database suffixes and their corresponding database names.
[root@server ~]# dsconf -D "cn=Directory Manager" ldap://server.example.com backend suffix list dc=example,dc=com (userroot)
This command displays the name of the back end database next to each suffix. Use the suffix’s database name in the next step.
Set the DN cache size for the database. This example sets the DN cache to 20 megabytes.
[root@server ~]# dsconf -D "cn=Directory Manager" ldap://server.example.com backend suffix set --dncache-memsize=20971520 userrootRestart the Directory Server.
[root@server ~]# systemctl restart dirsrv.target-
Monitor the IdM directory server’s performance. If it does not change in a desirable way, repeat this procedure and adjust
dncache-memsizeto a different value, or back to the default of 10 MB.
Verification steps
Display the new value of the
nsslapd-dncachememsizeattribute and verify it has been set to your desired value.[root@server ~]# ldapsearch -D "cn=directory manager" -w DirectoryManagerPassword -b "cn=userroot,cn=ldbm database,cn=plugins,cn=config" | grep nsslapd-dncachememsize nsslapd-dncachememsize: 20971520
Ressources supplémentaires
- nsslapd-dncachememsize in Directory Server 11 documentation
