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Wednesday, May 4, 2011

CREATING A STANDBY DATABASE USING RMAN - (UNIX / LINUX) - Pre-reqiusites

Pre-requisites

Pre- requisites for creating the standby database using RMAN are as follows.

Target database must be mounted or open
$ sqlplus "/ as sysdba"
SQL*Plus: Release 9.2.0.5.0 - Production on Mon Jan 3 19:42:02 2005
Copyright (c) 1982, 2002, Oracle Corporation.  All rights reserved.
Connected to an idle instance.
SQL> startup open
ORACLE instance started.
Total System Global Area  252777660 bytes
Fixed Size                   451772 bytes
Variable Size             218103808 bytes
Database Buffers           33554432 bytes
Redo Buffers                 667648 bytes
Database mounted.
Database opened.

Enable Archiving

If archiving is not enabled, issue the following statements to put the primary database in ARCHIVELOG mode and enable automatic archiving:

SQL> SHUTDOWN IMMEDIATE;
SQL> STARTUP MOUNT;
SQL> ALTER DATABASE ARCHIVELOG;
SQL> ALTER DATABASE OPEN;

Enable Forced Logging

Place the primary database in FORCE LOGGING mode after database creation using the following SQL statement:

SQL> ALTER DATABASE FORCE LOGGING;

This statement can take a considerable amount of time to complete, because it waits for all unlogged direct write I/O to finish.

Create a Password File

Create a password file if one does not already exist. Every database in a Data Guard configuration must use a password file, and the password for the SYS user must be identical on every system for redo data transmission to succeed

Configure a Standby Redo Log – For real time apply

A standby redo log is required for the maximum protection and maximum availability modes and the LGWR ASYNC transport mode is recommended for all databases. Data Guard can recover and apply more redo data from a standby redo log than from archived redo log files alone

Perform the following steps to configure the standby redo log.

Step 1   Ensure log file sizes are identical on the primary and standby databases.

The size of the current standby redo log files must exactly match the size of the current primary database online redo log files

Step 2   Determine the appropriate number of standby redo log file groups.

Minimally, the configuration should have one more standby redo log file group than the number of online redo log file groups on the primary database. However, the recommended number of standby redo log file groups is dependent on the number of threads on the primary database. Use the following equation to determine an appropriate number of standby redo log file groups:
(maximum number of logfiles for each thread + 1) * maximum number of threads

Step 3   Verify related database parameters and settings.

Verify the values used for the MAXLOGFILES and MAXLOGMEMBERS clauses on the SQL CREATE DATABASE statement will not limit the number of standby redo log file groups and members that you can add. The only way to override the limits specified by the MAXLOGFILES and MAXLOGMEMBERS clauses is to re-create the primary database or control file.

Step 4   Create standby redo log file groups.

To create new standby redo log file groups and members, you must have the ALTER DATABASE system privilege. The standby database begins using the newly created standby redo data the next time there is a log switch on the primary database.

SQL> ALTER DATABASE ADD STANDBY LOGFILE GROUP 10
     2> ('/oracle/dbs/log1c.rdo','/oracle/dbs/log2c.rdo') SIZE 500M;

Step 5   Verify the standby redo log file groups were created.

To verify the standby redo log file groups are created and running correctly, invoke a log switch on the primary database, and then query either the V$STANDBY_LOG view or the V$LOGFILE view on the standby database once it has been created.

SQL> SELECT GROUP#,THREAD#,SEQUENCE#,ARCHIVED,STATUS FROM V$STANDBY_LOG;

A valid full database backup of the target database

From the target (primary) database, you will need to create a full backup of the database.
RMAN> backup database plus archivelog delete input;
RMAN> list backup summary;

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