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nsslapd-db-page-size(5dsconf)

NAME | Description | Attributes | See Also

NAME

nsslapd-db-page-size – size of database pages in bytes

Description

Specifies the size of the pages used to hold items in the database, in bytes. Valid page sizes are 512, 1024, 2048, 4096, 8192, 16384, 32768, and 65536 bytes. If the page size is not explicitly set, Directory Server defaults to a page size of 8192 bytes. Ideally, page size is set such that entries fit in database pages without wasting space. Whether it is possible to achieve an ideal database page size depends on your entries, and on whether they are subject to change in size.

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Note –

You must be prepared to export all databases to LDIF, remove existing databases, and import all databases from LDIF when modifying this attribute.

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For ZFS file systems, you may find performance is best when the file system block size is set to equal the database page size. For example, try setting both to 32K or 64K.

To change the value of nsslapd-db-page-size, perform the following steps.

1. Shut down the Directory Server instance using the dsadm command.

2. Back up the Directory Server databases to LDIF using the dsadm command.

3. Remove all existing database files.

   These files include subdirectories of the database directory, database transaction logs under the nsslapd-db-logdirectory directory, and everything under the nsslapd-db-home-directory directory.

4. Change the value of the attribute in dse.ldif.

5. Restore the Directory Server databases from LDIF using the dsadm command.

6. Restart the Directory Server instance using the dsadm command.

Changing this default value can have 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.

The following list describes the characteristics of this configuration attribute.

Entry DN

cn=config,cn=ldbm database,cn=plugins,cn=config

Valid Range

512 bytes to 64 KB

Default Value

8192 (bytes)

Syntax

Integer

Example

nsslapd-db-page-size: 8192

Attributes

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPE	ATTRIBUTE VALUE
Availability	SUNWldap-directory
Stability Level	Obsolete: Scheduled for removal after this release

See Also

dse.ldif(4)

NAME | Description | Attributes | See Also