Oracle9i Data Guard Concepts and Administration Release 1 (9.0.1) Part Number A88808-01 |
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Oracle9i provides the ability to perform true database archival from a primary database to a standby database when both databases reside on a Real Application Cluster. This allows you to separate the log transport services processing from the log apply services processing on the standby database, thereby improving overall primary and standby database performance. Figure D-1 illustrates a standby database configuration on a Real Application Cluster.
In Figure D-1, the numbers within circles indicate local connections and the numbers within boxes indicate remote connections.
When you use the standby database on a Real Application Cluster, any instance can receive archived logs from the primary database; this is the receiving instance. However, the archived logs must ultimately reside on disk devices accessible by the node on which the managed recovery operation is performed; this is the recovery instance. Transferring the standby database archived logs from the receiving instance to the recovery instance is achieved using the cross-instance archival operation, performed on the standby database.
The standby database cross-instance archival operation requires use of standby redo logs as the temporary repository of primary database archived logs. Using the standby redo logs not only improves standby database performance and reliability, but also allows the cross-instance archival operation to be performed. However, because standby redo logs are required for the cross-instance archival operation, the primary database must use the log writer process (LGWR) to perform the primary database archival operation.
Perform the following steps to set up log transport services on the standby database:
LOCATION
attribute of the LOG_ARCHIVE_DEST_1
initialization parameter.
SERVICE
attribute of the LOG_ARCHIVE_DEST_1
initialization parameter.
Perform the following steps to set up log transport services on the primary database:
SERVICE
attribute of the LOG_ARCHIVE_DEST_
n
initialization parameter.
Ideally, each primary database instance should archive to a corresponding standby database instance. However, this is not required.
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