HP UX Red Hat Direry Server Software Miscellaneous Tuning Tips, Disabling Durable Transactions

Chapter 15. Tuning Directory Server Performance

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 Server1.

2.

Use the ldapmodify2 command-line utility to add the nsslapd-db-durable-transactionsattribute 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-transactionsattribute, 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-valattribute 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-transactionattribute must be set to on.

To specify or modify transaction batching while the server is running, use the ldapmodify2 command-line utility to add the nsslapd-db-transaction-batch-valattribute 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-valattribute, 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

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