nsslapd-db-home-directory

database file location

Description

Used to fix a situation where the operating system endlessly flushes pages. This flushing can be so excessive that performance of the entire system is severely degraded.

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 MB.

For example, if your Solaris host seems excessively slow and your database cache size is around 100 MB or more, then you can use the iostat utility to diagnose the problem. Use iostat to monitor the activity of the disk where the Directory Server database files are stored. If all of the following conditions are true, then you can use the nsslapd-db-home-directory attribute to specify a subdirectory of a tempfs type file system.

The disk is heavily used, more than 1 MB per second of data transfer.
Service time is long, more than 100 ms.
There is mostly write activity.

Note:

The directory referenced by the nsslapd-db-home-directory attribute must be a subdirectory of a file system of type tempfs, such as /tmp.

If you have multiple Directory Server instances 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.

Finally, 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 committed. This is a symptom of an overly large database cache size being configured for your server. If this happens, reduce the size of your database cache size to a value where the server will start again.

Entry DN: cn=config,cn=ldbm database,cn=plugins,cn=config
Valid Range: Any valid directory name in a tempfs file system, such as /tmp.
Default Value: Not applicable
Syntax: DirectoryString
Example: nsslapd-db-home-directory: /tmp/ds1-db

Attributes

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

ATTRIBUTE TYPE	ATTRIBUTE VALUE
Availability	SUNWdsee7
Stability Level	Obsolete: Scheduled for removal after this release