HP UX Red Hat Direry Server Software manual Changing the Database Checkpoint Interval

Changing the Database Checkpoint Interval

themselves. Because the purpose of the transaction log is to aid in the recovery of a directory database that was shut down abnormally, it is a good idea to store the database transaction log on a different disk from the one containing the directory database. Storing the database transaction log on a separate physical disk may also improve directory performance.

To change the location of the database transaction logfile, use the following procedure:

1.Stop the Directory Server1.

service dirsrv stop instance_name

2.

Use the ldapmodify2 command-line utility to add the nsslapd-db-logdirectoryattribute to the cn=config,cn=ldbm database,cn=plugins,cn=config entry. Provide the full path to the log directory in the attribute.

For information on the nsslapd-db-logdirectoryattribute syntax, see the Directory Server Configuration, Command, and File Reference. For instructions on using ldapmodify, see Section 2.4, “Adding and Modifying Entries Using ldapmodify”.

3.Restart Directory Server.

service dirsrv start instance_name

2.4. Changing the Database Checkpoint Interval

At regular intervals, the Directory Server writes operations logged in the transaction log to the disk and logs a checkpoint entry in the database transaction log. By indicating which changes have already been written to the directory, checkpoint entries indicate where to begin recovery from the transaction log, thus speeding up the recovery process.

By default, the Directory Server is set up to send a checkpoint entry to the database transaction log every 60 seconds. Increasing the checkpoint interval may increase the performance of directory write operations. However, increasing the checkpoint interval may also increase the amount of time required to recover directory databases after a disorderly shutdown and require more disk space due to large database transaction log files. Therefore, only modify this attribute if you are familiar with database optimization and can fully assess the effect of the change.

To modify the checkpoint interval while the server is running, use the ldapmodify2 command-line utility to add the nsslapd-db-checkpoint-intervalattribute to the

cn=config,cn=ldbm database,cn=plugins,cn=config entry.

1For information on stopping the server on platforms other than Red Hat Enterprise Linux, see Section 3, “Starting and

ForSt ppingmoreServers”information. on the syntax of the nsslapd-db-checkpoint-intervalattribute, refer to

2 The LDAP tools referenced in this guide are Mozilla LDAP, installed with Directory Server in the

the Directory Server Configuration, Command, and File Reference. For instructions on using

/usr/lib/mozldap directory on Red Hat Enterprise Linux 5 i386; directories for other platforms are listed in ldapmodify, see Section 2.4, “Adding and Modifying Entries Using ldapmodify”.

Section 2, “LDAP Tool Locations”. However, Red Hat Enterprise Linux systems also include LDAP tools from OpenLDAP. It is possible to use the OpenLDAP commands as shown in the examples, but you must use the -xargument to disable SASL and allow simple authentication.

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