Redo and Archive Log Setup

By default, you can access both online and archive logs. You can configure Replication Agent to access only the online logs, but doing so requires you to turn Oracle automatic archiving off and requires Replication Agent to issue manual archive log commands to Oracle.

Note: If Replication Agent for Oracle is configured to truncate Oracle archive logs directly—rman_enabled is set to false and pdb_archive_remove is set to true—it must be installed on a host that has direct access to the Oracle archive log files.

Archive Log Access

When you are using the default, for archive log files to be accessed, configure Replication Agent to use the directory path where archive log files are located. By default, an Oracle instance creates multiple directories under the flash recovery area specified by the DB_RECOVERY_FILE_DEST parameter of the Oracle ALTER SYSTEM command, each directory corresponding to and named after a separate day. However, Replication Agent requires archived redo log files to reside in a single directory. Consequently, you must configure Oracle to archive to a single directory to be read by Replication Agent.

Note: To prevent conflicts with other archive file processes, you may want to configure Oracle to duplex the archive log files into an additional destination directory that is used only for replication.

For information on specifying archive log destinations for your Oracle environment, see the Oracle ALTER SYSTEM command and LOG_ARCHIVE_DEST_n parameter.

Note: Accessing Oracle archived redo logs that are stored as file-system files is discussed in this section. If the archived redo logs are stored using the Oracle ASM, see the discussion of Automatic Storage Management.
Replication Agent for Oracle requires that redo log archiving is enabled at your Oracle database:
alter database ARCHIVELOG;
Note: If you are using Oracle Real Application Clusters (RAC), you must enable redo log archiving for each instance in the cluster.
Verify that log archiving is enabled:
select log_mode from v$database;
If you are using Oracle RAC, use this SQL statement to verify that log archiving has been enabled:
select instance, name, log_mode from gv$database;

If ARCHIVELOG (ARCHIVELOG or MANUAL in Oracle 10g) is returned, then log archiving is enabled.

Archive Log File Access

In the Replication Agent, set the pdb_archive_path configuration property to the expected location of archived redo log files. You can also set the Replication Agent pdb_archive_remove configuration parameter to true to allow the Replication Agent to remove these archive log files when they are no longer needed to support replication.

The rman_enabled parameter enables Replication Agent to use the Oracle RMAN utility to truncate old archive log files. See the Replication Agent Reference Manual.

Replication Agent Archive Setup

When pdb_include_archives is set to true (the default), Replication Agent does not archive, and Sybase recommends that you configure Oracle to perform automatic archiving of redo logs.

When the pdb_include_archives configuration parameter is set to false, Replication Agent for Oracle also requires you to disable automatic archiving of Oracle redo logs. Archiving is performed manually by Replication Agent as the data in the online redo log files is replicated.

Replication Agent for Oracle requires these settings in your Oracle database depending on the Oracle version.

Parent topic: Oracle-Specific Considerations
Related concepts
Automatic Storage Management