Red Hat DIRECTORY SERVER 8.0 Command Reference Manual page 129

Parameter
Example
3.4.1.9. 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 Professional Services. Inconsistent settings of this
attribute and other configuration attributes may cause the Directory Server to be unstable.
For more information on database transaction logging, refer to the "Monitoring Server and Database
Activity" chapter in the Directory Server Administrator's Guide.
Parameter
Entry DN
Valid Values
Default Value
Syntax
Example
3.4.1.10. 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).
Database Attributes under cn=config, cn=ldbm database, cn=plugins, cn=config
Description
nsslapd-db-debug: off
Description
cn=config, cn=ldbm database, cn=plugins,
cn=config
on | off
on
DirectoryString
nsslapd-db-durable-transactions: on
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