Red Hat Directory Server 8.0 Configuration, Command, and File Reference

Database Activity" chapter in the Directory Server Administrator's Guide.
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-durable-transactions: on
4.1.10. nsslapd-db-home-directory
This is usually applicable to Solaris only, and is used to fix a situation in Solaris where the
operating system endlessly flushes pages. This flushing can be so excessive that performance
of the entire system is severely degraded.
For users of other systems, 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.
If the Solaris host seems excessively slow and the database cache size is around 100
megabytes or more, then use the iostat utility to diagnose the problem by monitoring the
activity of the disk where the Directory Server's database files are stored. There are three
conditions required before resetting the nsslapd-db-home-directory attribute:
• 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
Database Attributes under cn=config,
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