[Q/A]: Database Refresh using RMAN Active Duplicate

Ans. Make sure you follow these guidelines for network-enabled database duplication. Both the source and destination databases must be known to Oracle Net.

• The source database can be mounted or open.
• If the source database is mounted, you must have shut it down cleanly prior to starting it up in mount mode.
• If the source database is open, it must be running in archivelog mode.
• You can continue to use the source database normally while the database duplication is going on, but be aware that there’s an overhead cost of CPU and network bandwidth consumption for sending the data.
• You must use a password file during active database duplication, unlike in the case of backup-based duplication, where a password file isn’t necessary. The password file makes it possible to connect to the auxiliary instance with the same SYSDBA password as the source database. You must use the same SYSDBA password for both the source and the auxiliary database. Alternatively, you can specify the password file option within the duplicate database command.

Step1: On DEV Host, Start the auxiliary database (duplicate database) instance. You must start the new instance in the nomount mode since you don’t have a control file for this new database yet. The contents of the SPFILE for the auxiliary instance will look like this:
db_name = dev

You need only one parameter, db_name, to denote the name of your new duplicate database.

SQL> connect / as sysdba
Connected to an idle instance
SQL> startup nomount

Step 2: Startup RMAN, and connect to the target (prod) database

RMAN> connect target sys/welcome1@prod

Step 3: Connect to the duplicate database using the keyword auxiliary through an SQL*Net connection:
RMAN> connect auxiliary dev
auxiliary database Password:

Step 4: Issue the duplicate target database command to start the database duplication process. If you were to perform the active database duplication on a different host with the same directory structure, your database duplication command must include the nofilenamecheck clause

RMAN> duplicate database
to dev
from active database
nofilenamecheck;

If the source database files are spread over multiple directories, you must use the set newname parameter instead of the db_file_name_convert parameter to rename the files in the duplicate database.

RMAN> run
{
set newname for datafile 1 to ‘/u01/app/oracle/testdata/system01.dbf’;
set newname for datafile 2 to ‘/u01/app/oracle/testdata/sysaux01.dbf’;
set newname for datafile 3 to ‘/u01/app/oracle/testdata/data01.dbf’;
set newname for datafile 4 to ‘/u01/app/oracle/testdata/index01.dbf’;
set newname for datafile 5 to ‘/u01/app/oracle/testdata/undotbs01.dbf’;
duplicate target database to dev
logfile
group 1 (‘/u01/app/oracle/testdata/logs/redo01a.log’,
(‘/u01/app/oracle/testdata/logs/redo01b.log’) size 10m reuse,
group 2 (‘/u01/app/oracle/testdata/logs/redo02a.log’,
(‘/u01/app/oracle/testdata/logs/redo02b.log’) size 10m reuse;
}

The run block shown here duplicates the target database and supplies file names for both data files and online redo log files for the duplicate database

Active database duplication works as follows regarding the various types of source database files:

• Data files are copied from the source database.
• Control files are re-created but will be copied from the source database if you specify the for standby clause.
• Tempfiles are re-created in the location set by the db_create_file_dest parameter.
• Online redo log files are re-created.
• Archived redo logs are copied from the source database, but only if needed for duplication.
• Server parameter files are copied from the source database if you use the spfile clause only.
• Password files are always copied for standby databases, but for a duplicate database, they’recopied only if you specify the password file option in the duplicate database command.