Red Hat Directory Server 8.0 Administrator's Guide

2.5. Disabling Durable Transactions

Durable transaction logging means that the temporary database transaction log is, in fact,

physically written to disk.

When durable transaction logging is disabled, every directory database operation is written to

the database transaction log file but may not be physically written to disk immediately. If a

directory change was written to the logical database transaction log file but not physically written

to disk at the time of a system crash, the change cannot be recovered. When durable

transactions are disabled, the recovered database is consistent but does not reflect the results

of any LDAP write operations that completed just before the system crash.

By default, durable database transaction logging is enabled. To disable durable transaction

logging, use the following procedure:

1. Stop the Directory Server

Use the ldapmodify

command-line utility to add the nsslapd-db-durable-transactions

attribute to the cn=config,cn=ldbm database,cn=plugins,cn=config entry, and set the

value of this attribute to off.

For information on the syntax of the nsslapd-db-durable-transactions attribute, 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 the Directory Server.

2.6. Specifying Transaction Batching

To improve update performance when full transaction durability is not required, use the

nsslapd-db-transaction-batch-val attribute to specify how many transactions will be

batched before being committed to the transaction log. Setting this attribute to a value of greater

than 0 causes the server to delay committing transactions until the number of queued

transactions is equal to the attribute value. For transaction batching to be valid, the

nsslapd-db-durable-transaction attribute must be set to on.

To specify or modify transaction batching while the server is running, use the ldapmodify

command-line utility to add the nsslapd-db-transaction-batch-val attribute to the

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

For more information on the syntax and values of the nsslapd-db-transaction-batch-val

attribute, refer to the Directory Server Configuration, Command, and File Reference. For

instructions on using ldapmodify, see Section 2.4, “Adding and Modifying Entries Using

ldapmodify”.

3. Miscellaneous Tuning Tips

Chapter 15. Tuning Directory Server Performance

468