Service manual

Transaction Logging
Chapter 8 Tuning Logging 147
Refer to the Sun ONE Directory Server Reference Manual for details concerning
individual configuration attributes.
Transaction Logging
Directory Server maintains database integrity through transaction logging. Upon
accepting an update operation —
add, modify, delete,ormodrdn —Directory
Serverwrites a log message about the operation to the transaction log. Durable
transaction logging, enabledby default, ensures data integrity. It does so by
ensuring each update operation is committed to the transaction log on disk before
the result code for the update operation is returned to the client application. In the
event of a system crash, Directory Server uses the transaction log to recover the
database. As the transaction log aids in the recovery of a database shut down
abnormally, consider storing the transaction log and directory database on
separate disk subsystems.
Transaction logging is extremely disk intensive, especially with durability turned
on. It is likely to be the major bottleneck for update performance. In addition to
protecting data integrity better in the event of a system crash, storing the
transaction log and database onseparate RAID systems such as Sun StorEdge disk
arrays can boost update performance. Table 8-7 provides further recommendations
for specific attributes.
dn: cn=Retro Changelog
Plugin,cn=plugins,cn=config
nsslapd-changelogmaxage
Specifies the maximum age for entries in the retro
changelog.
Change thisfrom0 (default, indicating no maximum)
to an interval after which clients using the retro
changelog have processed the log entries generated.
dn: cn=Retro Changelog
Plugin,cn=plugins,cn=config
nsslapd-changelogmaxentries
Specifies the maximum number of entries in the retro
changelog.
Change thisfrom0 (default, indicating no maximum)
to a maximum number of entries retained in the retro
changelog before trimming.
Table 8-6 Tuning Recommendations for Retro Change Logging (Continued)
Configuration Entry DN and Configuration Attribute Short Description and Tuning Recommendations